West, Ian M. 2015. The Purbeck Group of strata (Upper Jurassic - Lower Cretaceous) of Southern England; a Geological Bibliography: part of Geology of the Wessex Coast. Internet geological field guide. http://www.southampton.ac.uk/~imw/Purbeck-Bibliography.htm. Version: 31st October 2015.

Purbeck Group, Wessex Coast - Geology Bibliography
By Ian West,
Romsey, Hampshire
and Visiting Scientist at:
Faculty of Natural and Environmental Sciences
Southampton University,
Webpage hosted by iSolutions, Southampton University
Website archived at the British Library

|Home and List of Webpages
|Field Guides Introduction | Purbeck Bibliography - General | Purbeck Bibliography - Topics - Alphabetical |Purbeck Dinosaur Bibliography |Fossil Forests at Lulworth Cove - general |Purbeck Fossil Forests - Trees etc. |Purbeck Evaporites | |Purbeck Group & Palaeoenvironments. |Purbeck Group Analogues |Durlston Bay Bibliography |Sabkha, evaporites and modern arid environments |Durlston Bay - Peveril Point, Upper Purbeck Group |Durlston Bay, Middle Purbeck Durlston Bay - Lower Purbeck |Durlston Bay - Central Zigzag Part & Coast Erosion |Durlston Head - Lower Purbeck Group & Portland Stone |Durlston Bay - Bibliography |Portesham Rocket Quarry| |Paper - Evaporites and Associated Sediments of the Basal Purbeck Group (Upper Jurassic) of Dorset, by Ian M. West, 1975.

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An overview of the Middle to Upper Purbeck section in Durlston Bay, Dorset, from the Cinder Bed Ledge northward towards Peveril Point, 2007

Dinosaur footprints, Hard Slatt Bed, Hard Cockle Member, Lower Purbeck Group, Isle of Portland

Two examples of moulds of coniferous trees, Hard Cap, small quarry above Freshwater Bay, Isle of Portland, Dorset

The Jurassic-Cretaceous Purbeck Group or Purbeck Limestone Group comprises lagoonal limestones and shales. It contains a rich fauna and flora of crocodiles, turtles, dinosaurs (with footprints), mammals, gastropods, bivalves, serpulids, isopods, ostracods, insects, ferns, cycadophytes, coniferous trees, charophytes and algae. Rock types include biosparrudites, gastropod biomicrites, pelletoidal and stromatolitic limestones, marls, shales, gypsum, celestite beds, palaeosols and evaporite breccias. This is the first part of geological bibliography on these strata, which are very well-known nationally and internationally and have been studied geologically since 1814. The bibliography includes some abstracts and annotations and some illustrations.

A terminological point deserves attention at the start. It is the modern use of the names "Lulworth Formation" and "Durlston Formation". These are not good names because they actually break the rules of stratigraphic nomenclature. These are not true lithostratigraphic units (formations) but represent a renaming of divisions of the strata based on mixed chronostratigraphy and lithostratigraphy (ie. the old "Lulworth Beds" and "Durlston Beds"). There were set up for a special purpose by Casey (1963 p. 14), contrary to modern methods, at a time when the Jurassic-Cretaceous boundary was placed between these parts of the Purbeck strata, on the basis of circumstantial correlation with the Russian boundary. The Jurassic-Cretaceous boundary is now placed lower, and in any case the matter is not relevant to lithostratigraphy. Theoretically one should not to use these anomalous "formation" names or the term "Purbeck Limestone Group". However, they come into general use by the British Geological Survey so they are used here, where appropriate. They are not in the older geological literature which uses traditional terms. Whichever names are used the geological reader will in general understand the stratigraphical significance.

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Go to the - Topics, Alphabetical - section of the Purbeck Bibliography?

Internet Links regarding the Purbeck Group
(Go down for book and paper references.)

  • Bibliography and Index of Dorset Geology, by Jo Thomas and Paul Ensom, Dorset Natural History and Archaeological Society, 1989. First published in 1989 by The Dorset Natural History and Archaeological Society, Dorchester, Dorset DT1 1XA. Adapted for the World Wide Web in 2002 by John Palmer. © DNHAS, J. Thomas and P. C. Ensom, 1989 and 2002. [This is a key publication for finding papers on Dorset geology up to 1989.]

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    With references to other topics that are relevant to the Purbeck Group (Lulworth Formation and Durlston Formation - Upper Jurassic to Lower Cretaceous.

    This Purbeck bibliography is constructed alphabetically by author. This is the main Purbeck bibliographic or reference webpage. Preferably use this webpage. (Another webpage, an incomplete supplement, has references classified under topic, alphabetically .)

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    General References - Books and Papers (listed alphabetically)
    (where possible with abstracts or extracts of relevance)

    Abbink , O.A., Callomon, J.H., Riding, J.B., Williams, P.D.B. and Wolfard, A. 2001. Biostratigraphy of Jurassic-Cretaceous boundary strata in the Terschelling Basin, The Netherlands. Proceedings of the Yorkshire Geological Society, 53, 275-302, Abstract: The Jurassic-Cretaceous boundary beds in the Scruff Greensand Formation from Dutch sector North Sea wells L06-2 (between 2245.36m and 2262.76m) and L06-3 (between 2028.90m and 2037.80m) have yielded both ammonite faunas and abundant marine and terrestrial palynomorphs. Ammonite endemism in Europe was intense at the Jurassic-Cretaceous boundary. This means that pan-European correlations of Jurassic-Cretaceous boundary beds based on macrofossils are problematical. The ammonite faunas of wells L06-2 and L06-3 provide the most extensive and complete marine macrofossil record so far across the Volgian-Ryazanian (Jurassic-Cretaceous) boundary in the Spilsby Province and the North Sea Basin. The Primitivus, Preplicomphalus, Lamplughi, Runctoni and Kochi Zones have been identified. In both wells, the occurrences of the dinoflagellate cyst Gochteodinia virgula mean that the successions are no older than latest mid-Volgian. The dinoflagellate cyst associations of L06-2 are indicative of the late Volgian/early Ryazanian. The range tops of Gochteodinia virgula and Amphorula expirata are revised as a result of correlations with the ammonite zonation. Dinoflagellate cyst floras in L06-3 are indicative of the latest Volgian-?earliest Ryazanian. In particular. the co-occurrence of Batioladinium? gochtii and Gochteodinia virgula at 2030.60m in well L06-3 together with ammonite data, indicates that this horizon is of latest Volgian (Lamplughi Zone) age. Both wells contain reworked palynomorphs, including recycled older Late Jurassic dinoflagellate cysts. In addition, the palynological assemblages yield relatively diverse sporomorph associations. The sporomorph succession of both wells is used to establish an ammonite-calibrated sporomorph chronostratigraphy. Comparison with other studies suggests that the Jurassic/Cretaceous boundary occurs within the Cherty 'Freshwater' Beds of the Purbeck Limestone Group in Dorset, southern England, and within the Serpulite Member of Germany.
    Ager, D.V. and Wallace, P. The environmental history of the Boullonais, France. Proceedings of the Geologists' Association, vol. 77, pp. 385-417.
    Akahane , H., Furuno, T., Miyajima, H., Yoshikawa, T. and S. Yamamoto, S. 2004, Rapid wood silicification in hot spring water: An explanation of silicification of wood during the Earth's history. Sedimentary Geology, vol. 169, pp. 219-228. Abstract: A hot spring water lake in Tateyama Hot Spring has a high content of silica and readily precipitates silica spheres and deposits of opal. Abundant fragments of naturally fallen wood impregnated with silica were found in the overflow stream of the lake. These silicifications resulted from the precipitation of silica spheres onto split surfaces or cell walls of the fallen wood. The textures of wood tissues are the same as those found on naturally silicified wood formed in the vicinity of volcanic regions in the geological record. These results explain the formation mechanism of certain naturally silicified wood fragments that seem to be formed under the same conditions as those found in the hot spring water. To confirm the silicification process, fresh wood pieces of alder wood (Alnus pendula Matsumura) were placed in the hot spring water stream. Experimental wood fragments were silicified to nearly 40% by weight over a period of 7 years by the deposition of amorphous silica spheres in cell lumina of wood tissue. This study reveals that silicified wood can form under suitable conditions in time periods as short as tens to hundreds of years, and contributes to the understanding of the mechanisms forming silicified wood. [Not on the Purbeck Group, but relevant in showing that silicification of trees, like the Purbeck trees, can take place in a few years. The conditions discussed here are unlike those of the Purbeck; the Japanese situation is a hot spring with acid waters; the Purbeck silicification occurred with alkaline lagoon waters above. The paper is also useful as a source of reference on silicification of wood.]



    Ali , Y.A. 1981. Mineralogical, Geochemical and Sedimentological Studies on Recent Sabkha Sediments West of Alexandria, Egypt, and Some Upper Jurassic Evaporites from Dorset, England. Ph.D. Thesis, Ain Shams University, Cairo, Egypt, 332pp. By Dr. Yehia Abdel Hameed Ali. Supervised by Professor Ezzeldin Hilmy and Dr. Ian West at Ain Shams and Southampton University. [Purbeck sabkha cycles etc - Hard Cockle Member]
    Recent sabkha of the northern coastal zone of Egypt near Alexandria and El-Alamein was investigated. This region has sufficient rainfall (16 - 19cm annually) to be almost semi-arid. The sabkha occurs in the First Depression, between a modern beach ridge (the Coastal Ridge) and a Pleistocene beach ridge (Abu Sir Ridge) to the south and in the Second Depression, south of the Pleistocene Ridge. The sabkha surface is of brown silt, sometimes salt-encrusted and with scattered small halophyte shrubs (dikaka).
    The sabkha deposits consist mainly of brown carbonate and quartz silt with evaporites, including gypsum, halite and celestite. Non-evapoirte components, mostly of detrital origin, include quartz, feldspars, heavy minerals, calcite, aragonite (skeletal), dolomite and clay minerals.
    Sampling was from pits and by coring. Petrographic, mineralogical and geochemical techniques were employed for the analysis of sabkha sediments, groundwater samples and extracted interstitial brines.
    The sabkha sequence was sub-divided into five zones with distinctive mineralogical characteristics through the vertical profile from beneath the groundwater level to the sabkha surface. The origin of the nodules of primary gypsum in Zone IV is explained by the brine chemistry.
    Groundwater brines are saturated with calcium sulphate but are only moderately hypersaline (about 60 parts per thousand). Interstitial brines move upward by capillarity through the silt of the sabkha in response to evaporation at the surface. A salinity gradient is established. They concentrated several times, becoming supersaturated with calcium sulphate at Zone IV. Precipitation causes the mMg2+/mCa2+ ration to increase to a high level (about 220).
    The Second Depression, the site of a former lagoon (Lake Mareotis), contains salt lakes and sabkhas. Blister salt crusts of halite and gypsum are developed together with salt polygons and some algal blisters. Mollusc shells on the surface and in the sediments result from former lagoonal conditions. Gypsum sand crystals are developed in the sediments of this depression. A recent rise of the water table in the Second Depression, due to drainage of irrigation water, explains the lack of large gypsum nodules.
    Some evaporite-bearing sequences from the Upper Jurassic Purbeck Group of southern England were studied and sub-divided into sabkha cycles. They are interpreted as a series of semi-arid sabkha cycles and discussed in the light of the Recent model from northern Egypt.

    Ali, Y.A., West, I.M. and Hilmy, M.E. 1980. Modern sabkha sediments and gypsum nodules from the Mediterranean Coast of Egypt. Second Scientific Conference of Egyptian Postgraduates Abroad, Egyptian Education Bureau, 4 Chesterfield Gardens, London, W.1, Part 4, pp. 136-151.

    Allen , P. and Keith, M.L. 1965. Carbon isotope ratios and palaeosalinities of Purbeck-Wealden carbonates. Nature, 208, 1278-1280.

    Allen, P. et al. 1998. Purbeck-Wealden (early Cretaceous) climates. Proceedings of the Geologists' Association, 109, 197-236. (Full list of authors: Allen, P, Alvin, KL, Andrews, JE, Batten, DJ, Charlton, WA, Cleevely, RJ, Ensom, PC, Evans, SE, Francis, JE, Hailwood, EA, Harding, IC, Horne, DJ, Hughes, NF, Hunt, CO, Jarzembowski, EA, Jones, TP, Knox, RWO, Milner, A, Norman, DB, Palmer, CP, Parker, A, Patterson, GA, Price, GD, Radley, JD, Rawson, PF, Ross, AJ, Rolfe, S, Ruffell, AH, Sellwood, BW, Sladen, CP, Taylor, KG, Watson, J, Wright, VP, Wimbledon, WA, Banham, GH ). Abstract: A multidisciplinary colligation including new data and analysis of the evidence for the climates of southern Britain during c. 140 Ma. to c. 120 Ma BP (Berriasian-Barremian - ? earliest Aptian). The climate was at first hot, semi-arid and 'Mediterranean' (rather than 'monsoonal') in type, probably with seasonally opposed winds (E/W). An irregular long-term trend of increasing rainfall in the moister seasons is evident. This was probably associated with establishment of predominant westerlies during the Jurassic-Cretaceous transition and slightly lower average annual temperatures thereafter until Barremian times. Causes proposed are frequent changes in the regional climatic system due to tectonically induced adjustments of relief under the special conditions of the semienclosed Purbeck-Wealden archipelago and increasing proximity of the widening Protoatlantic sea.

    Allen, P. and Wimbledon, W.A. 1991. Correlation of NW European Purbeck-Wealden (nonmarine Lower Cretaceous) as seen from the English type-areas. Cretaceous Research, 12, 511-526.
    Alonso-Azcarate, J., Bottrell, S.H. and Mas, J.R. 2006. Synsedimentary versus metamorphic control of S, O and Sr isotopic compositions in gypsum evaporites from the Cameros Basin, Spain. Chemical Geology, 234, Issues 1-2, 46-57.
    Abstract: Sulfate del 34 S and del 18 O and Sr isotope compositions are presented for Berriasian (Upper Jurassic) gypsum evaporites from the Cameros Basin, a continental basin in the Iberian ranges of northern Spain. Solute sources to the ephemeral lakes in which the evaporites formed are dominated by weathering of sediments containing older Keuper marine evaporites and granitic/metamorphic Variscan basement. Strontium isotopic ratios of the continental evaporites (87Sr/86Sr = 0.707882 to 0.707933) are elevated compared to the Keuper source (87Sr/86Sr = 0.707605 to 0.707799), most likely reflecting a radiogenic component from basement lithologies. Sulfate del 34 S in the continental evaporites (at around 18.2 permil V-CDT) is higher than any possible mixture of solutes to the basin. The degree of 34S enrichment is small (approx. equal to 3.7 permil) and is most likely the result of partial bacterial reduction of lake-water sulfate. The same process would also enrich sulfate in 18 O, but by only about 1 permil. Evaporite sulfate del 18 O (at around 21.7 permil V-SMOW) is, in fact, enriched by about 10 permil relative to sulfate sources to the basin. This large effect is most likely the result of re-equilibration of oxygen isotopes during low grade metamorphism of the basinal sequence. Sulfur and strontium isotopes in the evaporites remained internally buffered and thus unchanged during metamorphism while oxygen isotopes were open to exchange with aqueous fluid and/or interbedded carbonates that constituted a large exchangeable oxygen reservoir. The potential of sulfate oxygen to undergo isotopic exchange at elevated temperatures must be taken into account when interpreting the significance of evaporite sulfate oxygen data from units that have undergone deep burial or low grade metamorphism.
    Alonso-Zarza , A.M. 2003. Palaeoenvironmental significance of palustrine carbonates and calcretes in the geological record. Earth Science Review, 60 (2003), pp. 261–298.
    Anderson, E.J. about 1999. The Purbeckian, Dorset.
    The Purbeckian, Dorset. By Dr E.J. Anderson, Temple University, Philadelphia. [This website has good photographs and sketches of Purbeck strata. The present writer is not convinced, though, that the cyclical theory presented is correct with regard to Purbeck dates or details. While variations in climate and salinity are certainly indicated, the detailed significance is extremely difficult to unravel especially at a time of Late Cimmerian tectonics. See Horne (1995) for problems of faunicycles]

    Anderson , E.J. 1999. The cyclic structure of the 'Purbeckian'at the classic Sierra del Pozo section of the Prebetic (Berriasian) southern Spain. Abstracts, Geological Society of America, Annual Meeting, Denver (November) , p. 424.

    Anderson, E.J. 2000. Criteria for recognising an orbitally forced cyclic heirarchy: the 'Purbeckian' at the classic Sierra del Pozzo section (Berriasian) southern Spain. Sediment 2000, Abstracts, June, p. 20, Leoben, Austria.

    Anderson, E.J. 2001a. The cyclic structure of the Purbeck Group, Lower Cretaceous, Dorset, England. Abstracts, Geological Society of America, N.E. Section Meeting, Burlington, Vermont,March, p. 67.

    Anderson, E.J. 2001b. Assymmetrical facies patterns in orbitally forced 3rd, 4th, 5th and 6th order sequences: The Purbeckian of Dorset. Abstracts, SEPM Multidisciplinary Approach to Cyclostratigraphy, Workshop, Sorrento, May, pp. 12-13.

    Anderson, E.J. 2001c. Integration of bed descriptions, molluscan depth zones and faunicycles with an orbitally forced four-tiered hierarchy of lithic allocycles: In the Lower Cretaceous, Purbeckian of Dorset, England. Abstracts, 21st IAS-Meeting, Davos, September, p. 71.

    Anderson, E.J. and Goodwin, P.W. 1990. The significance of metre-scale allocycles in the quest for the fundamental stratigraphic unit. Journal of the Geological Society, London, 147, 507-518. [This theory may be the basis of some later studies of Purbeck "cycles" by Anderson, listed here. The present writer considers, however, that the interplay of Late Kimmerian movement, the variation from basin to shelf, the occurrence of subaerially exposed intervals of unknown length, the rarity of truely marine beds, the progressive palaeoclimatic changes and particularly the lack of appropriate absolute dates makes this theory unsuitable for interpretation of the highly variable and lagoonal, Dorset Purbecks. The discussion on limitations on Walther's Law is probably of relevance, though.]

    Anderson, E.J., Perry, L.L. and Stynchula, J.A. 2001. Lateral continuity and discontinuity of 100 ka eccentricity sequences within an orbitally forced cyclic hierarchy: The Purbeck Group, Lower Cretaceous, Dorset, England. Abstracts of the Geological Society of America, Annual Meeting, Boston, p. 323.


    Anderson, F.W., (Frederick William Anderson of the British Geological Survey) - Purbeck ostracod specialist - see Orbituary in Annual Report of the Geological Society, London, 1982. [Appointed assistant lecturer in Geology and Zoology at Southampton University College, now Southampton University, in 1928. Later Lieutenant Colonel in the Second World War and then Chief Palaeontologist at the Geological Survey. He wrote many papers on ostracods, especially Purbeck ostracods, and on other topics.]

    Anderson, F.W. 1932. Phasal deposition in the Middle Purbeck Beds of Dorset. Report of the British Association for the Advancement of Science for 1931, 379-380. [Early report of cyclicity in the Purbecks as shown by ostracod faunas. This is the start of F.W. Anderson's work. Extract: "Three phases may be recognised in the lower half of the Middle Purbeck. The beginning of each phase is marked by fresh-water deposits, grey marls and shell limestones containing Paludina, Unio, Cyrena and fresh-water Ostracods. Throughout the phase there was a gradual shallowing of the water and increase in salinity; towards the end deposition decreased and cherty limestones (shell breccias) are the typical deposit. Limneaa, Planorbis and Corbula are characteristic of this brackish water stage..."]

    Anderson, F.W. 1940. Ostracod zones in the Wealden and Purbeck Beds. Advancement of Science, London, vol. 1, part 2, p. 259.

    Anderson, F.W. 1941. Ostracoda from the Portland and Purbeck Beds at Swindon. Proceedings of the Geologists' Association, 51, 373-384. With plates 18 and 19.
    In a recent communication [Ann. Mag. Nat. Hist., vol. iii. 11th Series, 1939, pp. 291-310] the author revised the classification of the Purbeck and Wealden Ostracoda and described a number of new species. There still remained, however, many undescribed forms and the details of the classification required further investigation. This work had been almost completed and a summary of results was due to be presented at the British Association meeting in Dundee (1939) when war intervened and the author was recalled for military service [Anderson was an important military geologist]. At the urgent request of Mr. P.C. Sylvester Bradley, however, complete descriptions have been attempted of several new species collected by him from the Portland and Purbeck Beds at Swindon.

    Anderson, F.W. 1958. In: Wilson, V., Welch, F. B. A., Robbie, J.A. and Green, G.W. 1958. Geology of the Country around Bridport and Yeovil. Memoir of the Geological Survey of Great Britain, Explanation of sheets 327 and 312. 118-129. Purbeck ostracod zones given for the Purbeck outcrops in the east of the area.

    Anderson, F.W. 1962. Correlation of the Upper Purbeck Beds of England with the German Wealden. Liverpool and Manchester Geological Journal, vol. 3, pp. 21-32. [Durlston Formation, Purbeck Group, in modern terminology.]

    Anderson, F.W. and Barker, D. 1966. Some British Jurassic and Cretaceous Ostracods. (Paperback book). Published by the British Museum (Natural History). Bulletin of the Natural History Museum, vol. Vol. 11, part 9. 51pp. 9 plates, text-figs and 1 folding chart. By Frederick William Anderson and Dennis Barker. Available from Pemberly Natural History Books for 6 pounds and in stock (Oct. 2015). [ostracods, Ostracoda]

    Anderson, F.W. 1973. The Jurassic-Cretaceous transition: The non-marine ostracod faunas. In: R.Casey and P.F. Rawson (Eds.) The Boreal Lower Cretaceous. Seel House Press, Liverpool, Special Issue of the Geological Journal, 5, 101-110.

    Anderson, F.W. l985. Ostracod faunas in the Purbeck and Wealden of England. Journal of Micropaleontology, 4, pp.l-68. Abstract: The occurrence and abundance of ostracods found in 98 subdivisions (Faunicycles) of late Jurassic to early Cretaceous age in the English Purbeck and Wealden are summarised. Most of the taxa found are illustrated from holotype or other material and details of their ranges and abundance given in relation to each faunicycle. The characters of the ostracod assemblages and zones are decribed. Three new species (Cypriea brendae, C. hispida and Eoparacypris edmundsi) ; also two new subspecies (Cypridea setina pelota and C. tuberculata dorsiclavata) are described and figured. A lectotype for Palaeocytheridea pellucida is selected and figured.

    Anderson, F.W. and Barker, D. 1966. Some British Jurassic and Cretaceous ostracoda. Bulletin of the British Museum (Natural History), Geology, Vol. 11, No. 9, London. Pp. 433-487; 9 Plates; 32 Text-figures. Comprises: 1. Anderson - New Genera of Purbeck and Wealden Ostracoda. 2. Barker - Ostracods from the Portland Beds of Dorset. 3. Barker - Ostracods from the Portland and Purbeck Beds of the Aylesbury District.

    Anderson, F.W. and Bazley, R.A.B. 1971. The Purbeck Beds of the Weald (England). Bulletin of the Geological Survey, U.K. 34, 1-173.

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    Anderson, Paul, E.

    Anderson, P.E., Benton, M.J., Trueman, C.N., Paterson, B.A. and Cuny, Gilles. 2007 (online 2006).Palaeoenvironments of vertebrates on the southern shore of Tethys: The nonmarine Early Cretaceous of Tunisia. By: Paul E. Anderson, Michael J. Benton, Clive N. Trueman, Bruce A. Paterson and Gilles Cuny. Journal - Palaeogeography, Palaeoclimatology, Palaeoecology, vol.243, Issues 1-2, January 2007, pp. 118-131.
    Abstract: Through the Late Jurassic and Early Cretaceous, the southern shore of the Tethys Ocean migrated north and south over short distances. These vicissitudes are documented in the 'continental intercalaire', a long series of mainly non-marine sediments deposited across North Africa. A combined taxonomic, physical and chemical taphonomic study provides independent lines of evidence for reconstruction of palaeoenvironments within this marginal marine setting. The Douiret, Chenini and Oum ed Diab formations from the Tataouine basin of southern Tunisia span the later part of the Early Cretaceous. Microvertebrates from four sites in these formations show different modes of physical abrasion, time averaging, and mixing, based on a taphonomic analysis using a combination of physical and chemical methods. The taxonomic composition of each assemblage, and trends in rare earth element (REE) compositions of bones, from each locality were used as independent lines of evidence to indicate differences in early depositional environments. The Jebel Boulouha assemblage (Douiret Formation) is interpreted as a terrestrial carbonate-rich environment with relatively little mixing. The Touil el Mra assemblage (Oum ed Diab Formation) suggests a marginal marine environment with some mixing of previously interred bones. The Oued el Khil assemblage (Chenini Formation) and the Oum ed Diab assemblage (Oum Ed Diab Formation) are more equivocal, suggesting mixed freshwater and marine influences. Interpreting salinity in marginal marine settings is difficult, and best attempted from multiple, independent lines of evidence. We suggest that REE geochemistry can contribute to palaeoenvironmental reconstruction when used in combination with other, independent physical physical, palaeontological and /or geochemical methods.

    Andrews, J.E. 1986. Algal laminae with calcite pseudomorphs after gypsum from the Middle Purbeck of Durlston Bay, Dorset. [Durlston Formation] Proceeding of the Dorset Natural History and Archaeological Society, vol. 107, pp 187-189. By Dr. Julian E. Andrews, at that time at the Grant Institute of Geology, University of Edinburgh.
    Limestone from the Upper Jurassic - Lower Cretaceous Purbeck Formation [Purbeck Group] of southern England have long been of interest with regard to preservation of fossil algae. Such limestones are best known from the Lower Purbeck where the 'caps' contain moulds of former filamentous algae (Pugh 1968). Although algal limestones have been reported from higher horizons in the Purbeck Formation, for example in the Soft Cockle Member (House 1986, Ensom 1985a) they are relatively uncommon. During field studies, Clements (1969) suggested that millimetre scale, pale-grey to buff laminations at the base of the argillaceous limestone bed DB 175 from northern Durlston Bay (SZ 036783) were algal laminae. This bed is located in the Middle Purbeck Corbula Member. El-Shahat (1977) recorded algal laminae in two horizons of the Corbula Member at Durlston Bay including DB 175; El-Shahat (1977) and Ensom (1985a) both record algal laminae in two horizons of the Corbula Member at Worbarrow Tout 17 km to the west (SY 898796). As far as the present author was aware the suggestion that these laminae were of algal origin has not been verified by petrography. Hence material from this bed was collected in September 1983 in order to conduct a petrographic study. ....
    [Note that Plate 5 and Plate 6 show lenticular pseudomorphs after gypsum in a central area.]

    Andrews , J.E. 1988. Soil-zone microfabrics in calcrete and in desiccation cracks from the Upper Jurassic Purbeck Group of Dorset. Geological Journal, 23, 261-270.

    Andrews, W.R. and Jukes-Browne, A.J. 1894. The Purbeck Beds of the Vale of Wardour. Quarterly Journal of the Geological Society, London, 50, 44-69.
    Anonymous . 1962a. Dinosaur passed this way. Evening Echo, Bournemouth , January 17 1962. "In a quarry high above Swanage the footprints (seen above) of an ancient dinosaur have been unearthed. It is believed to the first complete track of such footprints found. The foot-wide prints were made by a giant Iguanodon lizard over a hundred million years ago..." continues. Also article entitled: 'Echo' man follows the 100,000,000 year trail. Also photographs of the footprints in Suttle's Quarry.

    Anonymous. 1962b. The slow march of a Purbeck Iguanodon. New Scientist, No. 271, 25 January 1962. p. 186 in Notes and Comments. [But see Charig and Newman (1962) , below, who described three trackways and consider that they were not necessarily made by an Iguanodon and consider that a carnivorous bipedal dinosaur may have been responsible.

    Anonymous. 1963. New discovery of dinosaur prints in Swanage Quarry. Evening Echo, Bournemouth, Tuesday, 25 June 1963. "Sensational discovery made on Saturday by a team of experts from the British Museum investigating the dinosaur tracks in a Swanage quarry is that a series of smaller prints running with the tracks are made by the front legs of the massive creatures. Mr B.H. Newman of the Fossil Department of the British Museum, in charge of operations, claims that this supports his theory that the creatures walked on all fours, not upright, as commonly supposed in the past. " I regard this as conclusive proof of a theory that I have canvassed for many years," he told a reporter in the quarry on Saturday afternoon. The team had spent that day lifting and packing on to a lorry the last of the pieces of stone bearing dinosaur footprints. He told how earlier that day he had been painting in the last numbers on fragmented pieces of stone, so that they can be reassembled at the Museum, when he noticed that small indentations near the larger footprints recurred frequently along the trackway. So he examined them very closely, washed out the small cavity and checked the dimensions of each one. They were three toed and symmetrical and he is satisfied that they were made by the front paws of the pre-historic creatures. .. As reported previously the iguanodon tracks found in the quarry of Messrs J. and E. W. Suttle near the Municipal Caravan Site on Swanage quarries land are the longest continuous stretch of double prints ever found in this country. ..The original discovery 17 months ago was of a single line of 13 footprints running north to south. Six of these prints have been taken up to London. "This of course is a herbivorous creature and the nature of the foot much more fleshy, much less birdlike than the other prints, which were bigger and perhaps more importantly set. These ran transversely from the others, being east to west and were made by a megalosaurus. This was a "fairly large carnivorous bipedal dinosaur" and the prints were one foot by one foot (30cm) and in parts over an inch (2.5 cm) deep. .. Pointing out the front footprints he said that they were made by one curved digit and two smaller digits, he added "and they occur so regularly in association with the hind prints that they cannot be dissociated. He wished to make it clear that though earlier reports referred, correctly, to 150 yards (about 150 metres) total length of trackway discovered, not all was taken to the British Museum. About 75 ft ( 23 m) of the side by side tracks had gone and 35 ft (11 m) of the single track. .. Mr. Newman paid tribute to Mr John Suttle and his younger brother Mr Wilf Suttle who had given tremendous help and made the operation possible. This must have been at great financial cost to themselves and their only reward is the knowledge that it is due to them that this important discovery - the most significant of its kind in Europe - will be preserved for ever in the national collection." [There are other newspaper cutting of 1962 and 1963 discussing the excavation and study of these footprints. Other person involved were Mr E.F. Oppe of Worth Matravers, Mr P.A. Brown of Corfe Castle, Mr J.B. Delair, and Dr A.J. Charig of the British Museum, who has published photographs of the trackway.]

    Anonymous. 1981. (Title not known but on dinosaur footprints from Townsend Road, Swanage.) Daily Telegraph, Newspaper, 12 September, 1981. [More than 100 dinosaur footprints discovered on a plot of land at Swanage, Dorset, five weeks ago, were moved to the County Museum at Dorchester yesterday. Most of the prints were made by the three-toed Megalosaurus 150 million years ago.]

    Anonymous. 1987. Footprints of 'new' dinosaur found in quarry [Sunnydown Farm Quarry, near Swanage]. Evening Echo, Bournemouth (newspaper), 28 April 1987. Extracts: " A series of footprints found in a small quarry near Swanage, which were made by a type of quadrupedal dinosaur, have been recovered from .. the Purbeck Beds. The first clue to the unusual nature of the discovery was the extraction of a very large, 76 cm long and 61 cm wide cast of an apparently four-toed footprint (photograph was provided). .. With the agreement and help of the owners Mr. and Mrs. R. Notley, Dorset County Museum, owned and run by the Dorset Natural History and Archaeological Society, has so far lifted an area of limestone and revealed many more footprints on the site at Sunnydown Farm Quarry. These have truncated and therefore much shorter, front foot casts just in front of those made by the back foot. Not only are there at least three tracks made by quadrupedal dinosaurs, but also a large number of tridactly footprints criss-crossing the site. ..So far sieving and painstaking sorting of residues has yielded many hundreds of minute crocodile teeth, a small teeth of carnivorous dinosaurs, a fragment of a tooth belonging to an herbivorous dinosaur, numerous fragments of lizard jaws and the teeth of a flying reptile (pterosaur)... Still more exciting and quite unexpected is the discovery of mammal teeth. These are very small, some less than half a millimetre across. They represent the first major finds of such remains sicne first half of the last century when S.H. Beckles opened his famous mammal pit above Durlston Bay, near Swanage." [For more information on Sunnydown Farm Quarry and the discoveries see the work of Paul Ensom of the Natural History Museum, London. ]
    Arkell - Dr. William Joscelyn Arkell, the well-known, Jurassic Geologist, Palaeontologist and geological author, of the about the 1940s and 1950s.

    W.J. Arkell
    Arkell, W.J. The late Dr William Joscelyn Arkell of Oxford University, famous expert on and author of many publications on the Jurassic System. From a painting commissioned by Shell Oil Co. for an International Symposium on the Jurassic System. The photograph was kindly provided by the late Professor Michael House.

    Arkell, W.J. 1933. The Jurassic System in Great Britain. Clarendon Press, Oxford, 681pp. 41 plates. By Dr. William Joscelyn Arkell of Oxford University in 1933. Reprinted lithographically in Great Britain at the University Press, Oxford, by Vivian Ridler, printer to the university, 1970.
    Preface: In England, in the sphere of Jurassic geology, we are wardens of a classic area, for our cliffs and quarries are the standards of comparison for the whole world. A German authority, Dr. Hans Salfeld, remarked after a brief study in 1941: 'Research on the fauna and their succession shows that the English Upper Jurassic can be taken as the type of that in North-West Europe, in the most complete development anywhere yet known.' He had studied only the Upper Jurassic, but the same could be said of the Lower.
    The "Purbeck Beds" [i.e. Purbeck Group] are discussed in Chapter 16, pp. 518-539. In the following Chapter, 17, "The End of Jurassic Time and the Cretaceous Boundary" are discussed. There have been many changes in stratigraphical terminology since the book was first published, but it still contains subject matter of interest.

    Arkell, W.J. 1934. Whitsun Field Meeting, 1934, The Isle of Purbeck . Proceedings of the Geologists' Association, 45, 412-419. Report by the Director, W.J. Arkell, M.A., D.Sc., F.G.S.

    "On Friday evening, May 18th, about 40 members and guests assembled at the headquarters in Swanage, Craigside Hotel, where the Director gave a short lantern lecture on the geology of the Isle of Purbeck. The routes to be taken on the four days of the field meeting were explained, and slides were shown illustrating the principal geological features to be visited.

    Saturday, May 19th. Swanage to Studland.

    The party made the trip to Studland by motor-boat, a special boat having been engaged from the Gondolier fleet of Poole. By coasting along the chalk cliffs from Ballard Paint to the Foreland a fine view was obtained of the Purbeck Thrust Fault, lit by the morning sun. The caves and pinnacles carved out of the chalk by the sea, and the stratification marked by the rows of flint nodules, showed to perfection.
    On landing at Studland, the way was first led along the beach northwards and up the new road to the top of the knoll by the Knoll House Hotel. From this view-point the Director gave a short resume of Captain Diver's interesting researches on the origin of Littlesea and the sand dunes spread out below. The first sharp rise ascended by the party was the old sea-cliff of the Eocene beds, which was traceable northwards all along the west shore of Littlesea. The broad belt of sandhills to the east of this consists of blown sand and is a recent accretion, far the most part grown up since the beginning of the Seventeenth Century. There are three main rows or ridges of sand. The first, or inner, ridge is covered entirely by heather and ling and looks from a little distance like the Eocene heath beyond Littlesea; the third or outer ridge is of fresh appearance, tufted only with marram grass. A hogs-back of sand on the beach, already colonised by marram grass, seems to be the embryo of a fourth dune ridge. The Director pleaded far the logical naming of the ridges in the order of their formation, the oldest being called the first, instead of in inverse order as had been done by Captain Diver. He also referred to the richness of these heaths in all forms of natural history products - entomological, botanical and zoological-and to the desirability of preventing, by farming a strong public opinion, their exploitation and permanent defacement for the enrichment of the speculative builder when the present ownership comes to an end.

    The Agglestone Rock was next visited, and its origin by weathering of the Bagshot Beds was discussed. The path through the heaths gave an opportunity to see something of the calcifuge flora-heather, heaths, gorse, sundew, etc. - typical of the Bagshot Beds and forming such a marked contrast with the floras of the Mesozoic rocks to be visited on the succeeding days.

    The walk back to Studland brought the party to the Banks Arms Hotel at 1 o'clock, where some had their lunch, which they had brought with them, while others preferred it on the beach below. After lunch the brightly variegated Bagshot Sands in the cliff at Redend Point were examined, and the origin of the long vertical pipes with ironstone linings formed a subject for speculation. The Director gave a short account of the Lower Tertiary strata of this end of the Hampshire Basin, referring especially to the westerly overlaps in the sequence, the passage of the Bagshots into gravel, and to the Poole and Wareham pottery industry. The junction of the Reading Beds and the Chalk were next examined in the southern corner of the bay, and the nature of the unconformity was discussed. From here the party ascended the cliff through the rather dense undergrowth and walked round the cliff-top to Swanage Bay.
    At Punfield Gap the Director gave an account of the" Punfield Beds" controversy and pointed out the exact positions of the Perna Bed, Judd's so called" marine band," and other features of interest. Members then examined the section, from the Wealden Shales to the Chalk, with the help of copies of the description culled from the various chapters of Strahan's memoir, which had been duplicated and handed out in the morning with diagrams of the cliffs and a geological map of Purbeck. The section was studied at some length, and members returned along the beach to Swanage at their leisure, in time for a late tea. The total distance walked was 6 miles.

    Sunday, May 20th. Durlston Bay and Tilly Whim Caves.

    In the morning some members made an unofficial excursion in private cars to Lulworth and the fossil forest. In the afternoon the whole party walked to Peveril Point and thence round Durlston Bay as far as the faults, to examine in detail the type section of the Purbeck Beds. Many fossils were collected from the Purbeck Marble, Corbula Beds, Cinder Bed, and Mammal Bed - the last yielding some very well preserved minute freshwater gastropods. Special attention was drawn to the zonal value in these strata of the ostracods, and to the work of Forbes, Rupert Jones, Koert, Maillard, Merrett and others in correlating them with the equivalent beds in Wiltshire and Oxfordshire, the Weald, Germany and the Jura Mountains. The Director also laid stress on the evidence of an important marine incursion all over the South of England during the Middle Purbeck, as shown by the Cinder Bed, and the presence of Hemicidaris, Trigonia, Perna, Mytilus, Pecten, Protocardia, etc., and many marine fish, in the Cinder and Feather Beds and the Purbeck Building Stones. In spite of Salfeld's correlation of the German Serpulite with the Cherty Series of the Portland Stone, which also abounds in Serpulae, the Director held strongly that the view of all the earlier geologists was right; namely, that the Serpulite was the equivalent of the Middle Purbeck Beds and the Munder Marls of the Lower Purbeck Beds. All the evidence of the Ostracods and other fauna, as well as the detailed lithology of the whole Purbeck series, is in agreement with this view; and the Serpula of the Serpulite is S. coacervata Blumb.., which occurs in the Cinder Bed, while that in the Portland Stone is S. gordialis Schloth., which is not known in the Serpulite (See Arkell, 1933, pp. 550-1).

    Two interesting palceontological finds were mentioned by the Director; the discovery by Professor Hawkins of a colony of the rare Hemicidaris purbeckensis, comprising 38 tests and fragments of tests, in the Cinder Bed at this point (Quart. Journ. Geol. Soc., 1925, vo1. lxxxi, p. cxxviii) and the finding by himself last summer, in a thin band of mudstone a few feet below the Feather Bed, of numerous specimens of Archaeoniscus brodiei. This Isopod occurs in myriads in a similar bed in the Middle Purbeck of the Vale of Wardour, but it had not been previously located on the same horizon in Purbeck. The party, although numerous, were unsuccessful in finding Hemicidaris, Trigonia, Archaeoniscus or mammals. The Purbeck Beds, although highly fossiliferous, require much patient search to yield results.

    Climbing up the zig-zag path below Middle Durlston, the party walked to Durlston Castle for tea, and afterwards on to Tilly Whim Caves. At the end of the descent of the tunnel a short account was given of the succession of the Portland Stone displayed, special reference being made to the oyster bed and to the quarrying industry here and in Purbeck generally. In Grabau's "Text-book of Geology" (1920, pp. 812-3) are two photographs of Tilly Whim headed" Elevated sea-caves cut by waves in horizontal Jurassic strata." But we owe to Thomas Webster, who first explored this coast geologically on behalf of Sir H. Englefield ("Picturesque Beauties of the Isle of Wight," 1816, plate 33) an accurate engraving of the" caves" as they appeared in 1811, with the quarrymen still at work. Quarrying, in fact, has alone been responsible for the cutting of these and the many similar galleries and ledges between Durlston and St. Albans Heads.

    Some of the party inspected Anvil Point lighthouse, and all found their way home on foot in their own time.

    Monday, May 21st. Winspit, St. Alban's Head and Chapman's Pool.

    Leaving the motor-coaches at Worth Matravers, members descended the valley to Winspit, where they studied the whole succession of the Portland Stone down to below the middle of the Cherty Series. The Freestone Series was studied in the abandoned quarries and the Cherty Series in the cliff-path and sea-ledges below, where a serpulite composed of S. gordialis is well exposed. At the end of the coastguards' path to St. Alban's Head, another quarry in the upper part of the Freestone Series was visited on the point of the headland. Here the Under Freestone has become thin and cherty and is not worked, and the floor of the quarry is formed by the Chert Vein, the stone wrought being the Pon or Pond Freestone. This quarry provides a particularly fine section of the Shrimp Bed and Purbeck Caps.

    On emerging from the quarry a visit was paid to the Norman chapel before beginning the descent of Pier Bottom to Chapman's Pool, where lunch was taken on the grass slope above the Pool. From this vantage point the Director gave an account of the stratigraphy of the Portland Sand and Upper Kimeridge Clay of the surrounding cliffs; and drew attention to the reexcavated valleys here and at Winspit, mentioned in a recent paper by Mr. Burton (1932).

    The afternoon was quickly passed on the shore of Chapman's Pool and under Hounstout, collecting ammonites (chiefly Pavlovia rotunda and allied forms) from the Rotunda Nodules and Crushed Ammonoid Shales. The party then walked up Coomb Bottom and by way of Renscombe Farm to Worth. Tea was spread ready in the garden of the Post Office stores.

    After tea the motor-coaches were taken to Corfe, where some members alighted to see the castle, while the main body turned south to visit the remarkable tufa deposit near Blashenwell. The quarry still showed a good section about 5 ft. deep, and numerous land gastropods and artificially flaked flint chips were soon found, together with plant impressions, and some charcoal and limpets, left by the Neolithic men who worked the flints. A lively discussion arose as to the mode of origin of the deposit (see Reid, 1896).

    On the way the motor-coaches were stopped at Kingston to visit the Eldon memorial church, built entirely of Portland Stone and Purbeck Marble quarried on the estate. Opened in 1880, it is the last example of an extensive use of the Viviparus marble, and is most effective.

    The total walking distance during the day was 7 miles."
    [end of extract. The report continues with Tuesday May 22nd - Purbeck Hills, Worbarrow and Kimeridge. finally - "Tea was taken in the Castle Tea Rooms at Corfe, on a lawn overlooking the castle, and Swanage was reached in time for members to catch the 5.27 train to Waterloo. The total distance walked during the day was 3 and a half miles." A reference list is given.]

    Arkell, W. J. 1935. The Portland Beds of the Dorset Mainland. Proceedings of the Geologists Association, vol. 46, part 3, pp. 301-347. By W.J. Arkell, M.A., D.Sc., F.G.S. Received 3rd September 1934; Read 7th December, 1934.
    [This is a key paper on the Portland Stone Formation of the Dorset mainland. It has good and very informative photographs and diagrams. A significant part of it has been reproduced in Arkell (1947). In addition to the information on the Portland Group there are brief summaries of the sequences of basal Purbeck strata at Holworth House, Poxwell, Chalbury Camp etc. Although in traditional quarryworkers terms they are useful as confirmation of later work on these sequences(West, 1975). It is of passing interest to notice that William Joscelyn Arkell managed to get to some rather inaccessible places, like the eastern end of Gad Cliff in the 1930s, presumably before he had health problems.]

    Arkell, W.J. 1938a. Three tectonic problems of the Lulworth district: studies of the middle limb of the Purbeck Fold. Quarterly Journal of the Geological Society, London, 94, 1-54. By William Joscelyn Arkell, M.A., D.Sc., F.G.S. No abstract. Example extract: Introduction etc.: "Of all the folds thrown up across the Chalk plains of North-West Europe during the Alpine orogeny, the most interesting and the most perfectly exposed is the Purbeck anticline. In the cliffs of the Dorset coast the sea has laid bare all parts of the structure, from the core or crestal region, through the vertical and overturned middle limb and the "foresyncline" (Busk 1929, p. 29), into the foreland, where the Upper Cretaceous rocks are seen reposing with sharp unconformity upon a previously folded and eroded Jurassic foundation. The general and some special aspects of the fold and its associated faults have been discussed in a previous paper (Arkell, I936). The present paper results from a study of the middle limb, where it is dissected by the sea cliffs of the Lulworth district. These cliffs have long been renowned for their beauty, but their marvellous tectonic features, both great and small, have been neglected, with the result that their value to students of tectonics has not been fully utilized. The first three parts of the paper attempt a solution of the three most outstanding problems: contortions in the Purbeck Beds, the Purbeck Broken Beds, and the abnormal attenuation of the strata towards Durdle Door. The fourth part offers an interpretative essay and synthesis. The area dealt with is included in sheet 342 of the Geological Survey one-inch map and sheet 141 of the Ordnance Survey one-inch map.
    Contortions in the Purbeck Beds: (a) Description. The contortions in the Purbeck Beds at Stair Hole are illustrated in Pl. I. The top of the Portland Stone and the hard "Cap" limestones of the basal Purbeck Beds dip northward at 40 degrees, forming the arches through which the sea enters. In the sides of the little recess the rest of the Purbeck Beds, above the top of the Cypris Freestones, consisting of alternations of limestone and marl, shale, or clay seen in dipsection, begin to assume from below upwards an increasingly large knee-shaped anticlinal bend. The apex of the bend is directed upwards and outwards, towards the north, with the short horizontal limb to the south. The longer limb stands vertical or slightly inverted, and where the beds composing it plunge below the beach they are directed to meet the top of the Cypris Freestones at an angle of 50 degrees. In the Corbula and Beef Beds (upper part of the Middle Purbeck) and Upper Purbeck strata, the sharp apex of the anticline becomes blunter with increasing size. In these beds, near the top of the east cliff, a second but smaller sharp anticline develops above the horizontal limb of the other. This is of the same type as the larger flexure, with the apex pointing in the same direction, but it is more overturned northwards, and it does not affect strata below the Cinder Bed. There are signs of a third fold just below the top of the cliff, but the upward continuation has been eroded away. The intervening synclines are closed and approaching recumbent. This structure, which may be called the Lulworth crumple, is continued in the direction of strike for a visible distance of a mile and a half, but the other sections are not so good. On the west side of Stair Hole (Pl. I and Fig. 4) only the main anticline and syncline are seen, at a higher elevation above the beach, showing that the crest-line is rising westward. At Dungy Head and Durdle Door only the lower part of the structure survives, truncated by the cliff top...."[continues].

    Arkell, W.J. 1940. Dorset Geology, 1930-1940. Proceedings of Dorset Natural History Archaeological Society, 61, 117-135.

    Arkell, W.J. 1941. Report on the Mollusca from the Pebbly Sand below the [Portland] Roach Bed at Swindon. Proceedings of the Geologists' Association, vol. 51, part 4, pp. 385-399. By W.J. Arkell, M.A., D.Sc., F.G.S. Received 6th March 1940.
    Mr. P.C. Sylvester Bradley's stratigraphical researches have shown that special importance attaches to the Lower Pebbly Bed (TGA 9) of his description of the old Town Gardens Quarry, Swindon. This bed rests with a sharp line of demarcation on the poorly-fossiliferous Swindon Sands and Stone and is overlain by marlstones and marls of 'Purbeck' appearance, above which follows the 'Portland' Roach full of casts of large marine shells, Aptyxiella portlandica, Trigonia gibbosa, Protocardia dissimilis, Pleuromya uniformis, Eomiodon cuneatum etc. The critical bed TGA 9 consists of a dirty brown sand, locally somewhat coherent and packed with broken shell, amongst which the most conspicuous are pieces of the same large Aptyxiella as occurs in the overlying Roach, but with the test preserved. The bed contains many more or less rounded pebbles of sandy and shelly limestone, and some carbonaceous matter.
    Descriptions follow of: Coelodiscus swindonensis, Delphinula portlandensis, Delphinula (Nododelphinula) boloniensis, Delphinula aff. vivauxia, Neritomaa minimus, Neritoma sinuosa, Viviparus spp., Valvata helicoides, Valvata sabaudiensis, Hydrobia chopardiana, Ampullospira ceres, Aptyxiella portlandica, Procerithium leblanci, Procerithium bradleyi, Nerineopsis pseudoexcavata, Acteonina hypermeces, Ceritella lorteti, Physa bristovii, Pseudomelania pupoides, Valvata cf. loryana, Nucula lorioli, Trigonia gibbosa.

    Arkell, W.J. 1941. The gastropods of the Purbeck Beds. Quarterly Journal of the Geological Society, London , vol. 97, part 1, 79-128. [Example extract - the start - follows:]
    Isolated occurrences of genera such as Viviparus and Valvata are known in Bathonian, Liassic and more doubtfully even earlier rocks, but the earliest assemblage of a dozen genera of unequivocally freshwater molluscs is found in the wonderful fauna of the Purbeck Beds. Attention was first called to it by Thomas Webster (1816, pp. 191-2) (see below, p. 81). His remark, "It is rather surprising that this very ancient freshwater formation should not have excited more attention," might almost be said to be still true; for since J. de C. Sowerby figured a couple of species of Viviparus from the Purbeck Beds in 1826 and six species of lamellibranchs in that year and in 1836 (in Fitton's memoir), no further Purbeckian mollusca have been adequately figured in this country or described in the English language.
    Edward Forbes was preparing a monograph on the invertebrate fauna of the Purbeck Beds when his work was cut short in 1854 by his death at the age of 39. All that appeared was a preliminary account, in which the genera Viviparus, Valvata. Lymnaea, Planorbis, Hydrobia, Physa, Melania, Cyclas, and Unio were recorded, and also many marine genera, but no species were mentioned. A number of MS. names were introduced by him on labels and in the Survey catalogues, and some of them have been used by other authors, but if any manuscript or type specimens existed they have disappeared.
    In 1856 Osmund Fisher published a detailed account of the stratigraphy of the Dorset Purbeck Beds, recording all the genera mentioned by Forbes and assigning them to their precise horizons. H. W. Bristow also noted many of them in his vertical sections of the Geological Survey, sheet 22 (1857). A useful reprint of the Durlston section with the beds numbered was published by Damon (1884, pp. 201-209).... [continues with systematic descriptions from page 83 onwards].

    Arkell, W.J. 1945. The names of the strata in the Purbeck and Portland stone quarries. Proceedings of Dorset Natural History and Archaeological Society, 66, 158-168.

    Arkell, W.J. 1947. [and 1952] The Geology of the Country around Weymouth, Swanage, Corfe and Lulworth. Memoir of the Geological Survey of Great Britain. 386pp. With Wright, C.W.and Melville, R.V. 2nd edition - 1952 with Addenda and Corrigenda. This is a key Memoir of the BGS, although now superseded by a later version.

    Arkell, W.J. 1956. Jurassic Geology of the World. Oliver and Boyd, xv + 806pp [an important book].

    Arkell, W. J. 1951. Dorset Geology 1940-1950. Proceedings of Dorset Natural History and Antiquarian Field Club. 72, 176-194.

    Armella, C., Cabaleri, N. and Leanza, H.A. 2007. Tidally dominated, rimmed-shelf facies of the Picun Leufu Formation (Jurassic/Cretaceous boundary) in southwest Gondwana, Neuquen Basin, Argentina. Cretaceous Research, vol. 28, Issue 6, December 2007, pp. 961-979. By Claudia Armella, Nora Cabaleri and Hector A. Leanza.
    Abstract: A palaeoenvironmental model for the Picun Leufu Formation (Jurassic/Cretaceous boundary), which crops out in the Neuquen Basin, Argentina, on the southwestern margin of Gondwana, is presented in this paper for the first time. Detailed stratigraphic sections exposed along National Road 40 where it crosses the Picun Leufu Creek (type locality) and in the Cerrito Caracoles area, were examined and sampled. Based on a combination of the sedimentological data obtained (facies/microfacies analysis) and the relationship between benthic macrofaunas and their taphonomic attributes, it is concluded that the formation reflects a tidally dominated, rimmed-shelf setting characterized by prograding bars dissected by channels and thick lagoonal facies with shoal developments. In the Cerrito Caracoles area, where only the basal part of the formation is exposed, it is interpreted to have been deposited in a shallow subtidal marine environment in which shelf margin facies with patch reefs have been recognized. [Of approximately Purbeck age].
    Austen , J. H. 1852. A guide to the Geology of the Isle of Purbeck and the South-West coast of Hampshire. Blandford. W. Ship, Printer and Publisher. 20 pp. By the Rev. John H. Austen, M.A. "The following sketch of the Geology of the S.E. of Dorset has been compiled from notes taken at various periods during three years' residence in the Isle of Purbeck, but which were unavoidably brought to a hasty conclusion, a circumstance which the writer trusts will be a sufficient excuse for any inaccuracies which it may contain. He however anticipates that it will prove to be a sufficient guide to the stranger in this interesting district. Ensbury House, July, 1852." [The most important part with regard to the Purbeck Group is the log on pages 9 -14 with 129 beds at Durlston Bay listed. The record of fossils and old bed names is useful. Fisher's 1856 log is a modification of this.]
    Axsmith , B.J. 2006. The vegetative structure of a Lower Cretaceous conifer from Arkansas: further implications for morphospecies concepts in the Cheirolepidiaceae. Cretaceous Research, vol. 27, June 2006, pp. 309-317. By Brian J. Axsmith, Department of Biological Sciences, LSCB 124, University of South Alabama, Mobile, Alabama 36688, USA.
    Abstract: A reconsideration of the vegetative structure of a cheirolepidiaceous conifer with Pseudofrenelopsis parceramosa foliage is presented based on new collections from the Lower Cretaceous Holly Creek Formation (Aptian/Albian) of Arkansas. Analysis of these fossils contributes new data to an emerging whole plant concept, and allows for comparison with a previous reconstruction of a P. parceramosa plant from the English Wealden. The Arkansas vegetative shoots differ in lacking any open-sheathed leaves, the presence of papillae on all subsidiary cells, and the absence of a hypodermis. Furthermore, the Arkansas conifer exhibited helically arranged branches throughout, in contrast to the whorled branching of the Wealden plant reconstruction. The woods from Arkansas and England have identical thickened bars between the tracheid pits, and a similar arrangement of crossfield pits. However, the Arkansas wood has much higher rays, and lacks mixed pitting. These findings, along with previous accounts of significant differences in pollen cone structure, indicate that the Arkansas and English Wealden conifers represent different biological species with generally similar leafy shoots. Therefore, concepts regarding the biogeography, paleoecology, and phylogeny of P. parceramosa, most of which assume that this morphotaxon is a proxy for a single species of reconstructed plant, must be reconsidered.
    [This is not on the Purbeck trees but it of much interest because the author discusses a Cretaceous cheirolepidaceous conifer that like the Purbeck Protocupressinoxylon purbeckensis seemed to have lived in a high stress environment associated with evaporites. The general morphology of the Aptian/Albian Arkansas tree was one of helical branching rather than whorl branching as in the case of the Isle of Wight Wealden trees.]

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    Barbu, V. and Melinte-Dobrinescu, M.C. 2008. Latest Jurassic to earliest Cretaceous paleoenvironmental changes in the Southern Carpathians, Romania: regional record of the late Valanginian nutrification event. Cretaceous Research, vol. 29, issues 5-6, pp. 790-202. Life and the environment during the Cretaceous, 7th International Symposium on the Cretaceous. By Victor Barbu and Mihaela Carmen Melinte-Dobrinescu.
    Fluctuation in calpionellid, foraminiferal, and nannofossil diversity and abundance are documented in two successions located in the eastern part of the Upper Jurassic - Lower Cretaceous carbonate platform of the Southern Carpathian area, Romania. The lower part of the studied sections consists of upper Tithonian - upper Berriasian bioclastic limestones. This age is supported by the presence of the calpionellid assemblages assigned to the Crassicollaria, Calpionella, and Calpionellopsis Zones. Based on biostratigraphical data, a gap was identified within the uppermost Berriasian - base of the upper Valanginian (the interval encompasses the Boissieri, Pertransiensis, Campylotoxum, and lower part of the Verrucosum ammonite Zones). Hence, the upper Tithonian - upper Berriasian bioclastic limestones are overlain by upper Valanginian - lower Hauterivian pelagic limestones (the interval covered by the NK3B and NC4A nannofossil Subzones). A detailed qualitative and semiquantitative analysis of the nannoflora was carried out over this interval. To estimate the surface water fertility conditions, the nannoplankton-based nutrient index (NI) was calculated. The fluctuation pattern of NI allow us to recognize four phases in the investigated interval, as follows: (1) phase I (covering the lower part of the NK3B nannofossil Subzone and the upper part of the Verrucosum ammonite Zone, respectively) is characterized by low values of the NI (below 20%), by the dominance of the genus Nannoconus in the nannofloral assemblages (between 60-70%), and moderate abundance of Watznaueria barnesae (up to 23%), while the high-fertility nannofossils constitute a minor component of the assemblages; (2) phase II (placed in the NK3B nannofossil Subzone, extending from the top of Verrucosum ammonite Zone, up to the lower part of the Furcillata ammonite Zone) is characterized by increase of NI above 30%, a decrease of nannoconids (up to 50% at the top), while Watznaueria barnesae increases in abundance up to 27%. The fertility proxies (Diazomatolithus lehmanii, Zeugrhabdotus erectus, Discorhabdus rotatorius, and Biscutum constans) represent again a minor component of the recorded nannofloras (less than 7% in both sections), but they have an ascending trend; (3) phase III (which encompasses the boundary interval of the NK3B and NC4A nannofossil Subzones, corresponding to the upper part of the Furcillata ammonite Zone) contains higher NI values (over 35%, and up 52% towards the base of this phase), an abrupt nannoconid decrease (down to 20%), higher abundance of Watznaueria barnesae (over 30%), while the fertility nannofossils became an important nannofloral component, jointly amounting to almost 20%; (4) phase IV (identified within the NC4A Nannofossil Zone and corresponding to the boundary interval of the Furcillata and Radiatus ammonite Zones) is characterized by a decrease of NI to 25%, a recovery of the nannoconids up to 40%, a decline in abundance of Watznaueria barnesae to 25%, together with a pronounced drop of fertility taxa, which make together no more than 8%. We assume that maximum of eutrophication in the studied interval from the Southern Carpathians was in the Furcillata ammonite Zone. Notably, within the phases 2 and 3, the morphological changes identified in the benthic foraminiferal assemblages (the predominance of flattened morphologies, together with the presence of conical and trochospiral inflated forms), as well as the occurrence of the Zoophycos trace fossils and pyrite framboids, indicate dysaerobic conditions. In the Southern Carpathians, the late Valanginian-early Hauterivian biogeographical changes are coeval with the initiation of the carbonate platform drowning.
    Barker , D. 1966a. Ostracods from the Portland Beds of Dorset. Bulletin of the British Museum (Natural History), Geology, 11, 447-457, pls. 1-6.

    Barker, D. 1966b. Ostracods from the Portland and Purbeck Beds of the Aylesbury District. Bulletin of the British Museum (Natural History), Geology, 11, 459-487, pls. 7-9.

    Barker, D., Brown, C.E., Bugg, S.C. and Costin, J. 1975. Ostracods, land plants and charales of the basal Purbeck Beds of Portesham Quarry. Palaeontology, 18, 419-436. (Dennis Barker, Middlesex Polytechnic at Enfield, manuscript submitted June 1973, revised and resubmitted July 1974).
    A thin cherty layer near the base of the Purbeck Beds in Dorset has yielded a flora of land plants (including stems of Equisetum mobergii, isolated seeds referred to Carpolithes rubeola, C. glans, C. rhabdotus, C. cocos, C. gibbus, C. acinus and C. westi spp. nov., and cones of Araucarites sizerae sp. nov.) and freshwater Charales (Clavator westi sp. nov.) as well as freshwater ostracods. The discovery of Clavator westi in Lower Purbeck deposits opens up the possibility of separating the Lower Purbeck from the Middle Purbeck using the Charales. Among the ostracods Cypridea dunkeri Jones is shown to have stratigraphic value. Correlation of these basal Purbeck Beds in Dorset with the Swindon Series further north indicates that at Swindon either Purbeck conditions were established earlier than in Dorset, or that Portland conditions recurred later.
    [Contents Subjects: Introduction; Stratigraphical and Palaeontological Conclusions; The Charales; Charophyta; The Land Plants; Equisetales, Coniferales (Brachphyllum etc), Unclassified Seeds (Carpolithes and Cones, including Carpolites westi); Coniferales Araucariaceae (cone), Araucarites sizerae; References. This paper follows up the discovery of the Portesham Charophyte Chert by Ian West with a description of the fossil material collected by Ian West and Professor P.C. Sylvester Bradley in 1961. See: West (1961), Lower Purbeck Beds of Swindon Facies in Dorset. Nature. 190, p. 526.]

    Barrett, P. M., Clarke, J. B., Brinkman, D. B., Chapman, S. D. and Ensom, P. C., 2002, Morphology, histology and identification of the 'granicones' from the Purbeck Limestone Formation (Lower Cretaceous: Berriasian) of Dorset, southern England. Cretaceous Research, 23, pp.279-295.

    Barrett, P.M., Benson, R.B.J. and Upchurch, P. 2010. Dinosaurs of Dorset: Part II, the sauropod dinosaurs (Sauriischia, Sauropoda) with additional comments on the theropods. Proceedings of the Dorset Natural History and Archaeological Society, vol. 131, (for 2010), pp. 113-126. By Paul M. Barrett, Roger B.J. Benson and Paul Upchurch.
    Summary: Dorset has yielded a sparse, but regionally important, collection of sauropod dinosaurs. Most important among these is a specimen from the lower Kimmeridge Clay (Duriatitan humerocristatus gen nov., comb. nov.) which records the presence of a basal titanosauriform in the Late Jurassic of the UK. Material from the Purbeck Limestone Group is also important as it includes possible hatchlings and eggshell.
    Bate , R.H. and Robinson, E. 1978. A Stratigraphical Index of British Ostracoda. edited by Raymond H. Bate and Eric Robinson.
    Batten , D.J. 2002. Palaeoenvironmental setting of the Purbeck Limestone Group of Dorset, southern England. Pp. 13-20 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268pp. Report from a symposium on the Purbeck Group at the Dorset County Museum, Dorchester, Dorset, March 19-22, 1999.
    Bechly , G., Nel, A, Martinez-Delclos, X., Jarzembowski, E. A, Coram, R., Martill, D., Fleck, G., Escuillie, F., Wisshak, M. M. & Maish, M. 2001. A revision and phylogenetic study of Mesozoic Aeshnoptera, with description of numerous new taxa (Insecta: Odonata: Anisoptera). Neue Palaontologische Abhandlungen (Band 4).219 pp.
    Beckles , S.H. 1854. On the Ornithoidichnites of the Wealden. Quarterly Journal of the Geological Society, London , 8, 456-464. [First record of dinosaur footprints in the Purbeck Group.]

    Beckles, S.H. 1862. On some Natural Casts of Reptilian Footprints in the Wealden Beds of the Isle of Wight and of Swanage, Quarterly Journal of the Geological Society, London, vol. 18, 443-447.


    Beneult, D. 2015. La Vogue du "marbre de Purbeck" en Normandy aux XII and XIII siecles. [The Vogue of Purbeck Marble in Normandy during the Twelth and Thirteenth Centuries.] By Dominique Beneult. French Journal - Revue de la Manche, volume 57, part 229, pp. 3-19, with photographs, maps and footnotes. (There is detailed information, numerous references, and in addition, Dominque Beneult has kindly sent me a CD of excellent photographs of Purbeck marble toombs with Viviparus shells. At present filed with the reprints.)
    [My summary: The Purbeck Marble was brought over to Normandy, a relatively short sea journey from the Purbeck limestone outcrop at Swanage, Isle of Purbeck, Dorset. Examples are givn of its use in Normandy. They include the stone tomb of Richard de Reviers in the Abbey of Montebourg, of the Cherbourg Peninsula. The gastropod Viviparus cariniferus, is shown in a photograph to be obvious and abundant. Purbeck marble is also present in tombs in several cathedrals and churches of Normandy. These include Lisieux, Caen, Bayeux, Coutances, Mont-Saint-Michel, Poterson, and Paimpol. Details and discussion are given in this account, which is, of course, written in French. The author, to whom I am much obliged, has very kindly provided me with digital images of various tombs with well-preserved Purbeck Viviparus.]

    Beneult, D. and Renouf, J. 2015. Un presence anglaise a Beauport: le Marbre de Purbeck, 13 siecle. Dominque Beneult and John Renouf. 2015. An English presence at Beauport: the Purbeck Marble, 13th century. Les Cahiers of Beauport, no. 20, - 2015, pp. 46-48. One of the remarkable materials of Beauport Abbey (Paimpol, France) is a limestone containing numerous small fossil shells. Often designated under the name "lumachelle" it comes from Dorset on the south coast of England, and is called "Purbeck Marble". In several colours, grey, beige or green, it is polished and takes on the appearance of marble.
    Benfield , E. 1948. Purbeck Shop; A Stoneworker's Story of Stone. With an Introduction by Professor A.E. Richardson, A.R.A., F.R.I.B.A. Cambridge University Press. 172pp. Example extract on Durlston Bay ( p.9 ) : " A little farther on the lannen-vein sweeps to the cliff top, but as the cliff is growing higher the seam is in sight longer before it crops out into nothing. The lannen-vein has always been a favourite stone to dig, and as there is much more of it than the marble there many shafts where it has been dug; but it crops out near the foot of the hill, and therefore, as will be seen, was never as plentiful as the deeper seams. For there are other seams running to the cliff top in the same way, underlying the marble all through the hill and reappearing in Worbarrow Tout. The blue rag follows under the lannen-vein, and is succeeded by the freestone beds, which in their turn give way to the downs vein, and then the caps, and then the new-vein, all of them workable seams, with one other seam beneath them which no has ever dug because it is full of flints. " [An interesting book with some old photographs]

    Benfield, E. 1990. Purbeck Shop. A Stoneworker's Story of Stone. Introduction by Brian Bugler. Ensign. [by Eric Benfield].
    Bielecka , W. and Sztejn, J. 1966. Stratigraphy of the transition beds between the Jurassic and the Cretaceous, based on microfauna. Kwartalnik Geologiczny , 10, 96-115.

    Bielecka , W. 1975. Foraminifera and Brackish Ostracoda from the Portlandian of Polish Lowlands. Paperback book by Wanda Bielecka (Author).

    Abstract 296
    Introduction 296
    Characteristic of the Polish Lowlands Portlandian and its microfauna 298
    Microfaunal zonation of the Portlandian of the Polish Lowlands 301
    Comparison of the Uppermost Jurassic foraminiferal assemblages of the Polish
    Lowlands and Europe 303
    Systematic Part
    Family Lituolidae de Blainville, 1825 .
    Genus Haplophragmoides Cushman, 1910
    Genus Everticyclammina Redmond, 1964
    Genus Ammobaculites Cushman, 1910
    Genus Haplophragmium Reuss, 1860 .
    Genus Triplasia Reuss, 1854
    Family Ataxophragmiidae Schwager, 1877
    Genus Belorussiella Akimets, 1958
    Family Nubeculariidae Jones, 1875 .
    Genus Nubecularia Defrance, 1825
    Family Miliolidae Ehrenberg, 1835 .
    Genus Palaeomiliolina Loeblich and Tappan, 1964 .
    Family Nodosariidae Ehrenberg, 1838
    Genus Nodosaria Lamarck, 1812
    Cenus Citharina d'Orbigny, 1839 .
    Genus Citharinella Marie, 1938
    Genus Frondicularia Defrance, 1826
    Genus Geinitzinita Sellier de Civrieux Dessauvagie,
    Genus Lagena Walker & Jacob, 1798 .
    Genus Lenticulina Lamarck, 1804 .
    Genus Marginulina d'Orbigny, 1826 .
    Genus Marginulinopsis Silvestri, 1904
    Genus Planularia Defrance, 1826 .
    Genus Pseudonodosaria Boomgaart, 1949 . 346
    Genus Saracenaria Defrance, 1824 349
    Genus VaginuZinopsis Silvestri, 1904 . 350
    Family Polymorphinidae d'Orbigny, 1839 352
    Genus Eoguttuzina Cushman & Ozawa, 1930 352
    Genus Guttuzina d'Orbigny, 1839 353
    Genus Tristix Macfadyen, 1941 354
    Family Spirillinidae Reuss, 1862 357
    Genus SpiriZZina Ehrenberg, 1843 357
    Family Involutinidae Biitscheli, 1880 357
    Genus TrochoZina Paalzow, 1922 . 357
    Family Ceratobuliminidae Cushman, 19 - 7 359
    Genus PseudoZamarckina Mjatliuk, 1959 359
    Genus Epistomina Terquem, 1883 361
    Family Cyprididae Baird, 1845 . 362
    Genus Mantelliana Anderson, 1966 362
    Family Ilyocyprididae Kaufmann, 1900 363
    Genus Rhinocypris Anderson, 1940 363
    Genus Damonella Anderson, 1966 363
    Genus Cypridea Bosquet, 1852 . 364
    Family uncertain 368
    Genus Scabriculocypris Anderson, 1940 368
    Family Darwinulidae Brady & Norman, 1889 368
    Genus Darwinula Brady & Robertson, 1885 368
    Family Cytheridae Baird, 1850 . 370
    Genus Fabanella Martin, 1961 . 370
    Family Limnocytheridae Klie, 1938 371
    Genus Theriosynoecum Branson, 1933 371
    Family Cytherideidae Sars, 1925 . 371
    Genus Dicrorygma Poag, 1962 . 371
    Family Cytheruridae Milller, 1894 372
    Genus Orthonotacythere Alexander, 1933 372
    Genus Procytheropteron Ljubimova, 1955 373
    Family Progonocytheridae Sylvester-Bradley, 1948 373
    Genus Klieana Martin, 1940 373
    References 375

    Abstract: Foraminifera of the Lower and Middle Portlandian and Ostracods of the Purbeckian facies of the Upper Portlandian of Polish Lowlands were studied; 63 foraminiferal species (including 12 new) and 21 ostracod species (including one new, Cypridea praealta sp.n.) are described. Analysis of stratigraphic ranges of the microfauna made it possible to distinguish 5 foraminiferal zones (I-V) of the Lower and Middle Portlandian and 5 ostracod zones (F-B) of the Purbeckian facies of the Upper Portlandian. The foraminiferal microfauna of the Portlandian of Poland appears most similar to those from the Lower and Middle Volgian of the Russian Platform.

    Up to now, the foraminifers of upper part of the Upper Jurassic developed in epicontinental facies in western Europe were only occasionally studied by Guyader (1968), Groiss (1963, 1967 a, b, 1970), Hanzlikova (1965),
    Lloyd (1959) and others. The Upper Jurassic foraminifers from Poland were the subject of studies of Bielecka & Pozaryski (1954), Bielecka (1960) and Garbowska (1970). Much more attention has been paid to the foraminifers of the Lower and Middle Volgian of the USSR (Furssenko & Polenova, 1950; Dain, 1934, 1972; Dain & Kusnetzova, 1971; Ivanova, 1971; 1973; Kuznetzova, 1963, 1965, 1969; Mjatliu~, 1939, 1959; and others). The studies dealing with brackish ostracods of Poland (Bielecka & Sztejn, 1966; Marek, Bielecka & Sztejn, 1969) are of regional-stratigraphic character. The paper presents results of palaeontological and stratigraphic studies on foraminifers of the Lower and Middle Portlandian and brackish ostracods of the Purbeckian facies of the Upper Portlandian (where foraminifers do not occur) of the Polish Lowlands. The analysis of the microfauna was based on core material from boreholes drilled by the Geological Institute (Warsaw) and oil industry in years 1948-1972. The core material was derived from the areas of Kujawy swell, Warsaw basin, Baltic syneclize, L6dz and Mogilno basins and Pomerania (NW part of Pomeranian swell, Pomeranian basin and N part of Szczecin basin) (see Text-fig. 1). The ammonite zonal scheme of the Lower and Middle Portlandian (Table IV), proposed by Dembo~ska (1973), and ostracod zonal scheme of the Upper Portlandian develdped in the Purbeckian facies, proposed by Bielecka & Sztejn (1966), are accepted here. Over 40 borehole profiles (Text-fig. 1) with full or almost full coring were selected out of about 100 borehole profiles covered by the microfauna studies. The profiles selected yield more or less numerous microfaunal assemblages characteristic of a given part of Poland. Several foraminiferal species of the uppermost stage of the Jurassic, including some previously described by Bielecka & Pozaryski (1954) from Upper Jurassic strata of Central Poland, are revised. On the whole, 63 foraminiferal species (including 12 species and 2 subspecies new) and 21 ostracod species (including 1 new) are described (see Tables I-II). The palaeontological material is housed in the Geological Institute, Warsaw (abbr. IG). The species listed in Table III are not recorded in all parts of the Polish Lowlands. In particular parts a few species are missing. This primarily results from lithofacies differences and location of a given area in relation to the center of the basin. The microfaunaI assemblages are the richest in the center, becoming impoverished towards the periphery of the basin.

    Blake, J.F. 1880. On the Portland Rocks of England. Quarterly Journal of the Geological Society of London, vol. 36, pp. 189-236. By the Rev. J.F. Blake, M.A., F.G.S. (Read January 7th, 1880). [This is a good, old paper, with information on the familiar territory of the Isle of Portland, but also with data on Swindon and the Vale of Wardour and elsewhere. Some of the illustrations or etchings of Portland fossils in the Plates are very good, and there are descriptions of these Portland bivalves and gastropods. There are horizonal sections of the strata at Swindon. ]

    Bosence , D.W.J. 1987. Mesozoic platform carbonates and benthic calcareous algae of the Severn and Wessex Basins. In: 4th International Symposium on Fossil Algae, Cardiff, July, 1987, edited by Robert Riding. Pre-Symposium Field Excursion, Excursions Guide, pages unnumbered. [See section: Portland and Purbeck Groups of the Isle of Portland. End-Jurassic regressive sequence with oncoids, oyster/Solenopora reefs, trees, palaeosols and tufas.]
    Bradley - P.C. Sylvester Bradley. [This geologist and palaeontologist, at one time Head of the Geology Department at Leicester University, is more well-known as Professor Sylvester Bradley. Go down to "Sylvester Bradley" in this Bibliography for his papers.
    Braye , J. 1890. Swanage (Isle of Purbeck): Its History, Resources as an Invigorating Health Resort, Botany and Geology. 2nd Edition. William Henry Everett and Son, Salisbury Square, Fleet Street, London, 119 pp. (John Bray). Price One Shilling. [Notes: Introduction by L. Forbes Winslow, Physician to the North London Hospital for Consumption. Extract - " Swanage is happily placed with regard to good stone and marble, the Purbeck stone having been used for ages in paving the streets of London, and by the Government in military works at Portsmouth, Dover, and elsewhere. Certainly this should be sufficient guarantee of its durability and suitability for building a substantial town for the future generations. The minor question of cost should not not be an insurmountable obstacle. - If a gentleman wants a coat he goes to Savile Row or Bond Street - a working man finds his way to Hounditch. -- Much is said in the present day about sanitary buildings, but little of the foolish vagaries of those inflated gentlemen the architects, who have managed to spoil many of our pleasure places by putting up shoddy buildings of lath and plaster, and ticketing them with fantastic names such as "Bungalow". -- Such buildings are well suited to stand a few years in the tropics; but utterly worthless for a decent watering place, and the builders who errect them should be prosecuted for tempting frivolous and thoughtless pleasure-seekers to risk their lives in them." (and more in this style!). ---- Geology chapter by Horace B. Woodward, F.G.S. pp 63-82. Extract: "The Purbeck Beds mark changing conditions; freshwater limestones, botryoidal and tufaceous in character, like beds of travertine, are succeeded in places by evidences of land vegetation in the now silicified remains of Cycads and Conifers. The beds indicate that after the freshwater and terrestrial conditions, which may have been marked by a lake or a series of lagoons, a sudden irruption of the sea in Middle Purbeck times allowed the incursion of marine forms like the Pecten, Avicula, and Hemicidaris. These were succeeded by a gradual change from brackish to freshwater conditions in Upper Purbeck times, when the Unio, Physa, Valvata, Paludina, and Planorbis flourished. " (a good geological account, but note that, with modern knowledge, we now know that not all the points made in the extract are correct).]
    Bristow , H.W. 1856. Comparative Vertical Sections of the Purbeck Strata. Geological Survey of Great Britain, Nos. 1,2 and 3 by H.W. Bristow. No. 4 by the Reverend. Osmond Fisher and H.W. Bristow. Reference maps no. 16 and 17. Engraved by J.W. Lowry. No. 1 is the Durlston section by Bristow.

    Bristow, H.W. 1884. Section of the Purbeck Strata of Durlston Bay, Dorset. pp. 201-209 in: Damon, R. 1884. Geology of Weymouth, Portland and the Coast of Dorsetshire (2nd ed). Weymouth. [with a list of fossils from Durlston Bay, particularly mammals - 28 species of 15 genera.]

    Bristow, H.W. and Fisher, O. 1857. Vertical Section, Sheet 22, Geological Survey of Great Britain.

    Bristow, H.W. and Whitaker, W. 1959. Vertical Sections of the Purbeck Strata of Lulworth, Dorset. In Sheet 56, Horizontal Sections, Geological Survey.



    British Geological Survey (BGS). (Compiler Wood, M.A.) 2011. Geology of South Dorset and South-East Devon and its World Heritage Coast.

    The cover of the 2011 South Dorset Memoir of the British Geological Survey

    An example page from the British Geological Survey, South Dorset Memoir, 2011

    Special Memoir for 1:50,000 geological sheets 328 Dorchester, 342 West Fleet and Weymouth and 342/343 Swanage and parts of sheets 326/340 Sidmouth, 327 Bridport, 329 Bournemouth and 330 Newton Abbott. Compiled by M.A. Woods. By Barton, C.M., Woods, M.A., Bristow, C.R., Newell, A.J., Westhead, R.K., Evans, D.J., Kirby G.A., and Warrington, G. Contributors: Biostratigraphy - J.B. Riding; Stratigraphy - E.C. Freshney; Economic Geology - D.E. Highley and G.K. Lott; Engineering Geology - A. Forster and A. Gibson. British Geological Survey, Keyworth, Nottingham, 2011. 161 pp. This is the new version of the Geological Survey Memoir for the Dorset Coast etc. and replaces Arkell (1947) and the earlier memoir by Strahan (1898). It covers a wider area than these old memoirs, though, and includes all of "Jurassic Coast", UNESCO World Heritage Coast. It is a key reference work. Available from BGS Online Bookshop at 24 pounds stirling (in Jan. 2012).


    British Geological Survey. 2000 , Geological Map - Swanage, Sheet 342 east and part of 343 (2000 edition). Solid and Drift Edition. 1:50,000. This includes the Purbeck type section.

    British Geological Survey . 2000. Geological Map: West Fleet and Weymouth. 1:50,000 Series, England and Wales Sheet 341 and part of sheet 342. Solid and Drift, with seafloor geology, cross-sections and other data. New map. [This commences just to the west of Durdle Door, Lulworth and includes Bats Head. It extends from here westward to Abbotsbury, including all the Fleet Lagoon and the Isle of Portland. It provides a cover of most of the Weymouth Anticline. The continuation southward onto seafloor geology is something that the previous Weymouth and Fleet maps do not have. There are large, north-south cross-sections based on boreholes and seismic data. These show deep faulting and such features of interest as the thickness and distribution of evaporites in the Permo-Trias. It has good structural contour maps for the top Penarth Group and the top Corallian and other information, such as sea-floor sediment data for the offshore area around Weymouth and Portland.
    There are clearly different views on this map. It has been favourable reviewed by David Nowell (2001) in the Circular of the Geologists' Association No. 949 for December, 2001. Referring to this and the new sheet for Swanage (342 east and part of 343) and for Dorchester (328). Amongst other favourable points, he commented that: " These maps have completely revised stratigraphic units that more fully reflect the distribution of the different rock types and recognisable sequences within the sediments of southern Dorset that, across country, can be mapped in greater detail than was previously possible. The clearest changes are to the traditional lower, middle and upper divisions of the Chalk, which have been replaced by up to eight formations, while the Purbeck is divided into five members of the Durlston and Lulworth Formations. Another necessary change, even if it is slightly garish, is the effective use of red and grey tones to show the complex sand and clay variations within the Eocene sequence, which was deposited after the uplift and erosion of the Chalk.... These splendid maps can be thoroughly recommended to anyone who is interested in the picturesque and fascinating geology of southern Dorset. Flat or folded copies cost £9.95p. each and can be ordered from the Sales Desk, British Geological Survey, Nottingham, NG12 5GG (Tel. 0115-936 3241 Fax 0115-936 3488) or obtained by visiting the BGS London Information Office at the Natural History Museum (Tel. 020-7589-4090)."
    Although the Weymouth map certainly provide more details, in terms of members there are also, unfortunately, some problems, which no doubt will be corrected in later editions. Some of the defects have been discussed by the late Professor Michael House (2001) who has mapped the Weymouth area in detail. Most of these are not considered here, and reference should be made to this article. Most easily seen, and most affecting the coastal geology, are anomalies in outcrop and symbols in the offshore around Bats Head to White Nothe. The offshore rocks of Portland Stone at Bats Head, the Cow and the Calf have been placed not in a Portland outcrop but in the Chalk Group. As the late Professor Michael House (2001) pointed out out their Portland Stone composition has been known since 1818. Indeed, in the past the Geological Survey has always described them correctly. Strahan (1898), for example, stated "Its [Portland Stone] further course under the sea is marked by ..... by the Bull, and the Blind Cow, the Cow and the Calf Rocks, all portions of a submerged escarpment of vertical Portland Stone running parallel to the vertical Chalk of the adjacent coast." See also the data in Donovan and Stride (1961). The 1974 edition of the Weymouth map actually comments on "vertical, outlying rocks of Portland Stone". Furthermore there seem to be some other strange aspects of mapping in this area. The well-known foresyncline of Chalk here is shown with the symbols of an anticline and the Chalk outcrop is too wide. On the south side of the fold the Chalk is shown in apparently unconformable contact with the Portland and Purbeck strata. In fact, the "Late Kimmerian" unconformity here is the base of the Gault, not the Chalk. The Chalk could only be in contact with Purbeck by faulting, but a fault is not shown.
    The earlier British Geological Survey Map Offshore Map, the 1:250,000 sheet - Portland 50N04W clearly shows Gault and Upper Greensand between the Chalk and the Purbeck. The 1974 edition of the 1:50,000 Weymouth Sheet, 342, is clear, trustworthy and well-labelled and shows correct features in this Bats-Head to Whitenothe area. The new sheet of 2000 certainly contains much useful supplementary information but would be better if revised to deal with the specific problems.
    Another aspect, less important and already mentioned above, is the use of the so-called "Lulworth Formation"and "Durlston Formation". These names have been quite commonly used in the literature in the past even though they break the rules of stratigraphic nomenclature. These are not true lithostratigraphic units (formations) but represent a renaming of unsatisfactory divisions based on mixed chronostratigraphy and lithostratigraphy ("Lulworth Beds" and "Durlston Beds"). There were set up for a special purpose by Casey (1963 p. 14), contrary to modern methods, when the Jurassic-Cretaceous boundary was placed between them, on the basis of circumstantial correlation with the Russian boundary. The Jurassic-Cretaceous boundary, which is in any case now placed lower, is not relevant to lithostratigraphy. It is clearly preferable in the future, however, to follow normal stratigraphical rules and not to use these anomalous "formation" names. This confusion has also resulted in common use of the term "Purbeck Limestone Group". It is not used in these webpages because it is group of formations and the formation names are invalid. The name "Purbeck Group" is used in this website.
    Brodie , P.B. 1839. A notice on the discovery of the remains of insects and a genus of Isopodous Crustacea ... in the [Purbeck] Formation of the Vale of Wardour, Wilts. Proceedings of the Geological Society, vol. iii, 134-135.

    Brodie, P.B. 1845 A History of Fossil Insects in the Secondary Rocks of England. accompanied by a particular account of the strata in which they occur, and of the circumstances connected with their preservation. John Van Voorst, London, 130pp.

    Brodie, P.B. 1847. Notice on the existence of Purbeck strata with remains of insects and other fossils at Swindon, Wilts. Quarterly Journal of the Geological Society, London, vol. iii, 53-54.

    Brodie, P.B. 1854. On the Insect Beds of the Purbeck Group in Wiltshire and Dorsetshire. By the Rev. P.B. Brodie, M.A., F.G.S. Quarterly Journal of the Geological Society, London, vol. 10, pp. 475-482.
    [Includes a Middle Purbeck sequence with the Cinder Bed. This is at quarries on the south side of the River Nadder, near Teffont Mill. The Cinder Bed is 0.56 metres thick, and contains not only Praeexogyra and Protocardia, but also "Trigoniae". (Trigonia is present in the middle of the Cinder Bed of Durlston Bay with flattened Protocardia - see Arkell, 1947). The Middle Purbeck sequence above the Cinder Bed is thin compared with the Dorset sequence. Thin white sandstones, interbedded with the limestones are unusual features. Just over 0.6 metres above the Cinder Bed is an unusual and conspicuous reddish-brown, coarse laminated sandstone with Praeexogyra and Neomiodon. The sequence is very condensed and it is quite possible that this is roughly equivalent to the brown sandstones of the Intermarine Member in the Ridgeway Railway Cutting north of Weymouth (see Fisher, 1856), although Brodie did not make this comparison.
    Details regarding Durlston Bay or Durdlestone Bay, as it is referred to here, and the Ridgeway Cutting are also given in this paper.]

    Brodie, P.B. 1867. On the presence of the Purbeck Beds at Brill, in Buckinghamshire, etc.. Quarterly Journal of the Geological Society, London , 23, 197-199.
    Brown , P.R. 1961. Petrology of the Lower and Middle Purbeck Beds of Dorset. Unpublished Ph.D. thesis, Liverpool University, 205 pp.

    Brown , P.R. 1963. Algal limestones and associated sediments in the basal Purbecks of Dorset. Geological Magazine, vol. 100, pp. 565-573.

    Brown, P.R. 1964. Petrography and origin of some upper Jurassic beds from Dorset, England. Journal of Sedimentary Petrology, 34, 254-269.

    Browning , L. 1997. Durlston Marine Research Area: a status report on the physical environment, wildlife and human use. Purbeck Heritage, English Nature, 24 pp.
    Buckland , W.A. and De la Beche, H.T. 1836. On the geology of the neighbourhood of Weymouth and the adjacent parts of the coast of Dorsetshire. Transactions of the Geological Society of London, series 2, vol.4, pp. 1-46.

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    Calkin , J.B. 1933. Iguanodon footprints in Dorset. Discovery, v. 14, p. 13.

    Calkin, J.B. 1968. Ancient Purbeck: an account of the geology of the Isle of Purbeck and its early inhabitants. The Friary Press, Dorchester, 61pp. With 48 illustrations. Paperback booklet. Price 6 shillings. By J. Bernard Calkin, M.A., F.S.A. [With notes and illustrations regarding dinosaur footprints, fossil leaves, Roman mosaics, Purbeck Marble, Kimmeridge oil shale objects etc.]

    Carozzi, A. 1948. Etude Stratigraphique et Micrographique du Purbeckien du Jura Suisse. Faculte des Sciences, Universite de Geneve, 175 pp. Stratigraphic and Micrographic Study of the Purbeckian of the Swiss Jura. Thesis presented at the Faculty of Sciences at University of Geneva for the degree of Doctor of Science in Geology and Mineralogy. Thesis No. 1122. This work is in printed and published paperback book format.
    [This is a classic, early, petrographic study of the Purbeck Group, with quantitative data. Extract (which I have translated from the French): "The Purbeckian of the Swiss Jura presents two palaeogeographic domains that are quite distinct, already in part delimited by Maillard. The most extensive is the domain of the Lower Dolomitic Beds which covers the Vaudois Jura and the southern part of the Neuchatelois Jura and the Jura Bernois Jura. From the bottom to top there are 1. The Lower Dolomitic Beds (Lower Purbeck), 2. Lacustrine Beds (Middle Purbeck), and 3. Upper Brackish or Marine (Upper Purbeck)...
    To the north of this zone in the heart of the Neuchatelois Jura is the domain of the marls with gypsum. The type succession is from bottom to top: 1. Marls with Gypsum (Lower Purbeck), 2. Lacustrine Beds (Middle Purbeck), Upper Brackish or Marine Beds (Upper Purbeck)."
    A variety of interesting Purbeck topics are discussed including the Black Pebbles, the multicoloured breccio-conglomerates, the source of Mg, the charophytes, ostracods, the grumeleux limestones (also common in Dorset), the dolomites (cf. the Lower Purbeck dolomitic marls of Dorset), pelletoidal limestones ("pseudo-ooliths"), microbreccias, cargneules, celestite, gastropods, Dasycladiaceans (not present in Dorset), cylces of sedimentation, and faecal pellets. It has many graphic logs and maps and a good bibliography of the older Purbeck literature, much of which is not listed here. An important aspect is that Carozzi related Purbeck facies to palaeotectonics, with the dolomite facies of the Lower Purbeck girdling the gypsum facies which mostly occurs on the structural highs. The Dorset Purbeck is also, of course, affected by palaeotectonics - the well-known, Late Kimmerian. However, thickness variations are rather most noticeable in Dorset than the facies variations. Carozzi does not discuss the Dorset succession, but his work is useful for comparative purposes. Carozzi's thesis is an old classic and recommended reading for Dorset Purbeck enthusiasts.]


    Carozzi, A. 1955a. Dasycladacees du Jurassique superieur du bassin de Geneve. [Dasycladacean algae of the Upper Jurassic of the Geneva Basin]. Eclogae Geologicae Helvetiae, vol. 48, no. 1, 1955. With 19 figures and two plates. By Albert Carozzi, Geneva. [No abstract: Some notes on the content follow:
    This paper is mostly taxonomic. There are stratigraphic considerations on p. 64. The sequence is Sequanian to Kimmeridgian (Pterocerian and Virgulian), followed by Portlandian and finally Purbeckian. The distribution of species through this sequence is given. ]

    Carozzi, A. 1955b. Le Jurassique superieur recifal du Grand-Saleve, essai de comparaison avec les recifs coralliens actuels. [The reefal facies of the Upper Jurassic of Grand Saleve (Geneva), an essay of comparison with modern coral reefs]. Ecologae Geologicae Helvetiae, vol. 47, no. 2 for 1954. By Albert Carozzi, Geneva.

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    Casey , R. 1963. The dawn of the Cretaceous Period in Britain. Bulletin of the South-East Union of Scientific Societies, Bulletin No. 117, 1-15. Preprint of Presidential Address to the Geological Section. Tunbridge Wells, 11th April 1963. "Some regimes were born in violence and others flowed in on a silent tide. So it is in geology. Not every page of Earth's history is numbered by crustal upheavals, volcanic outbursts and similar revolutions: all too often it is hard to tell where one chapter ends and the other begins..." [This has been a key paper in linking the Cinder Bed with the basal Cretaceous transgression of the Boreal Realm. This interesting correlation with the Boreal Jurassic/Cretaceous boundary has been largely overshadowed by later work. New evidence has made it possible to relate the Purbeck lagoonal succession to the marine Jurassic/Cretaceous boundary as defined in southern France. This is not of the same age as the Russian Jurassic/Cretaceous boundary. A local bioproduct of placing the Jurassic/Cretaceous boundary in the middle of the Purbeck sequence in southern England has been to create a terminological problem. Because chronostratigraphy and lithostratigraphy were not correctly separated, this paper split the Purbeck into two mixed chronostratigraphic and lithostratigraphic subdivisions - the "Lulworth Beds" below the Cinder Bed and the "Durlston Beds" for the Cinder Bed and overlying strata upto the Hasting Beds (lower part of the Wealden). The "Lulworth Beds" were to be grouped with the Portland, and the "Durlston Beds2 as part of the Wealden, although this did not happen. Unfortunately, the base of the Cinder Bed was taken as a chronostratigraphic boundary, the J-K Boundary, but the Portland/Lulworth Beds boundary was placed lithostratigraphically and the Durlston Beds/Hastings Beds boundary was also placed on lithostratigraphic criteria. This unsatisfactory nomenclature later became used by others authors to create the so-called "Lulworth Formation" and "Durlston Formation". However, they are only names and probably some people find them convenient. The present author does not see any use for them and considers that they should be abandonned, with a return to the "Purbeck Group". Nevertheless, this is only one aspect of Casey's paper and there is much in it of value. It provides useful information on correlation within Britain, and on various details of strata tied in with the Cinder Bed. Casey's 1963 paper is not easily found but contains much interesting material.]
    Chapman , F. 1900. Remarks upon the Ostracoda [chiefly Lower Purbeck forms from the Thame Valley]. Proceedings of the Geologists' Association, 16, p. 58.

    Chapman, F. 1906. Note on an ostracodal limestone from Durlston Bay, Dorset. Proceedings of the Geologists' Association, 19, 283-285.
    Charig , A.J. and Newman, B.H. 1962. Footprints in the Purbeck. New Scientist , 14, 134-235. "Your issue of 25 January 1962, contained an editorial note on 'The slow march of the Purbeck iguanodon' (Anonymous, 1962b). This was based upon the comments which one us (A.J.C.) had made after preliminary inspection of the dinosaur footprints found in the quarry [Suttle's Quarry] at Herston, Swanage. [The bed, according to Suttle, see note below, is the pinkish top of the Roach, Clements' Bed 125] Further excavations have now revealed more of the trackways... [Three almost parallel trackways have been found. In each there is some small lateral displacement of prints made by left and right feet. About 10 metres of trackway was seen. The full stride as made by one foot (not the pace) was about 1.17m. They were not typically of Iguanodon in spite of the earlier article. Some of the prints in the trackways at Herston show such deep narrow toe-prints as to be almost bird-like, and the angle between the two outer toes is much more than 90 degrees. Carnivorous bipedal dinosaurs, such as Megalosaurus are discussed.] In any case, the Herston trackway was made by an animal far smaller than a fully grown Iguanodon bernissartensis, of which the approximate dimensions were cited in your note. The prints are a little less than half as long and half as broad as the skeleton of the foot of I. bernissartensis displayed in this Museum. We intend to publish a full illustrated account of these footprints."
    [Some photographs of the trackway are shown below. No scale is given but in length they appear to be not far off the length of the foot of the man shown. Incidently, according to Francis Charig to whom I am very grateful for the information, he is fossil bird specialist Cyril Walker who worked at the Natural History Museum for Dr Alan Charig. The left photograph is from this article but colourized. The right-hand one is from another source and not in the article.]

    Parallel trackways of theropod-type at Suttle's Quarry, Swanage in 1962 Dinosaur trackway of Suttle's Quarry shown in close-up.

    [See also below: Article by quarry owner Suttle (1962) on the same footprints, and, also, a brief note by Swaine with an inaccurate comment about a hypothetical slope]
    Cifelli , R.L. Early mammalian radiations. Journal of Paleontology, 75 (6), 1214-1226, Nov. 2001. [A major review which includes some discussion of Purbeck mammals, such as the Multituberculates and "Symmetrodonts" etc. It is important in providing an extensive, up-to-date reference list on mammals including those in strata of approximately Purbeck age in various countries. Most of these mammal references are not given here.]
    Clasby , C.S. 2003. A Study of the Research Potential and Environment of Deposition of a Set of Dinosaur Footprints from Suckthumb Quarry on the Isle of Portland, Dorset. Unpublished undergraduate research project, School of Ocean and Earth Science, Southampton University, 56pp. Abstract: A number of slabs of rock bearing the footprints of dinosaurs, have been found in a quarry on the Isle of Portland, Dorset. The slabs originate in the middle part of the "Cypris" Freestones of the Purbeck Limestone Formation. The cast of the trackway has been preserved in the base of a large freestone unit and it is this which has been discovered. Petrological studies reveal considerable lateral variation of the bed. This and the subsequent difficulties in correlating the Purbeck strata of the Isle of Portland to that of the more easterly type section are discussed. The footprints were formed on the salt-encrusted surface of an ephemeral lake in an evaporitic environment, but with little evidence of product other than pseudomorphs after halite. Gypsum does not appear to be as common in this sequence as elsewhere in the succession and this is believed to reflect a non marine recharge system. Within these beds organic remains, mainly plant and insect, are locally abundant, though largely fragmented. Well preserved pollen and spores have also been recovered, and the results of their study confirm the variance of the western Purbeck. [This is a report by Caroline Clasby on her third year student project with one copy filed at Southampton University.]
    Clements , R.G. 1967. Some notes on the Purbeck Beds.Proceedings of the Dorset Natural History and Archaeological Society, 88, 43-44. By Roy Clements, Leicester University.
    Recent work by the writer on the Gastropoda of the Purbeck Beds of this country, has revealed a number of points of more general interest about the Purbeck Beds of Dorset, some of which are included below.
    1. In the quarry to the east of the main Weymouth road, some 500 yards south of Poxwell Church (G.R. SY 744 836), the Purbeck succession begins with a one-foot bed of limestone full of the internal and external moulds of minute gastropods, small lamellibranchs, and ostracods. This is the basal cast bed (Arkell 1941, Quart. J. Geol. Soc. Vol. 97, p.79-128), which has also been recorded at Osmington, Ringstead and Chalbury Camp.
    A bakelite vacuum impregnation technique produced very good casts of the gastropods, etc., and also revealed the presence of moulds of sponge spicules in the bed. These are clearly distinct from those originally figured and described by Young (Geological Magazine, Vol. 15, p.220-1, fig. b.) as Spongilla purbeckensis, and recorded by Arkell (1947, Geology of the country around Weymouth, Swanage, Corfe and Lulworth p.133) as being abundant in certain Purbeck cherts. These are now regarded as being silicified pseudomorphs after lenticular gypsum crystals described by West (1964, Proceedings of the Yorkshire Geological Society, Vol. 34, pp. 315-330). The present specimens are mainly rod-like structures with irregular, finer branches, but one tetraxon was found, with one of the rays broken. As they occur as moulds, it seems likely that the spicules were. originally calcareous.
    The associated faunas show little sign of having been transported any great distance. The ostracods occur mainly as carapaces, and the gastropods very frequently have complete apertures. These faunas together with the associated sediments suggest a depositional environment for the bed of relatively quiet non-marine lagoonal conditions with salinities in the range of strongly brackish to possibly supersaline.
    2. In the spring of 1965, the writer was able to examine briefly the collections of Purbeck gastropods housed in the Dorset County Museum, Dorchester. On a piece of rock labelled as coming from Ridgeway, and of Cherty Freshwater Bed type lithology, a specimen of Planorbis fisheri Arkell was found showing remnants of colour patterning. This consisted of three spirally-arranged dark bands on the upper (adapical) surface of the last quarter of the last whorl. (The shell is regarded as sinistral by anology to present day Planorbidae). A very broad band was seen running around the middle of the adapical surface of the whorl, with a very fine band just abaxial to this, and a third of medium breadth rurming just above the peripheral keel.
    Traces of colour patterning are not uncommon on fossil gastropods. However, it is much more common for members of the Neritacea (as for example the quite frequent colour patterning in Theodoxus fisheri Arkell from many localities in the Purbeck beds), so this particular example is quite noteworthy.
    3. The residue obtained by normal micropalaeontological preparation of a sample taken from the lower Middle Purbeck of Durlston Bay was found to consist predominantly of the mineral celestite. The sample was taken from a lOin. bed of very dark grey/green shale (Bed 7 in the section given by Strahan, 1898, Geology of the Isle of Purbeck and Weymouth, p. 94, fig. 123, or the upper 10 ins. of Bed 27 of Damon's (1884, Geology of Weymouth, Portland and the coast of Dorsetshire, 2nd ed., p. 207 - version of Bristow's section) some 21 ft. below the Cinder Bed in the northern half of the bay.
    The mineral occurs as beef-like seam about a quarter of an inch thick, with the long axes of the crystals arranged perpendicular to the seam surfaces. It is nearly white, has a slight blue tinge, and gives a strontium flame test reaction. The occurence of this mineral in association with ostracods and gastropods of low salinity/freshwater typ:: poses some problems as to its origin. The fauna (particularly the ostracods) appears to be in place. It is thought possible that the celestite was formed shortly after the deposition of the bed by the circulation of high salinity ground waters.

    Clements, R.G. 1969. Annotated cummulative section of the Purbeck Beds between Peveril Point and the Zig-Zag Path, Durston Bay. [see below for "Clements' Log - reprinted in 1993]

    Clements, R.G. l969b. Contribution to section on the Purbeck Beds : In : Guide for Dorset and South Somerset. In Torrens,H.S. (Editor) International Field Symposium on the British Jurassic. Keele University. [This is the original Clements' Log of Durlston Bay, which was republished with minor updating as Clements, 1993 - see below.] 71 pp.

    Clements, R.G. l973. A Study of Certain Non-Marine Gastropods from the Purbeck Beds of England. Unpublished Ph.D. Thesis, University of Hull, 49l pp.


    CLEMENTS, R.G. 1993. TYPE-SECTION OF THE PURBECK LIMESTONE GROUP, DURLSTON BAY, SWANAGE , DORSET. [i.e. - Clements' Log] Type-section of the Purbeck Limestone Group, Durlston Bay, Swanage, Dorset. Proceedings of the Dorset Natural History and Archaeological Society, 114 for 1992, 181-206.
    [This important log, is a slightly updated version of the log of Clements (1969) in Torrens (1969). It is a key work and is essential for almost any field study in Durlston Bay; it is recommended that geologists with interest in the area, possess more than one copy of this work. It is needed for recognising particular beds. It has been used as the basis for various subsequent research and no serious geologist should go to Durlston Bay without it.]
    Abstract: A detailed bed-by-bed description is given of the Purbeck Limestone Group in its type-section of Durlston Bay, Swanage, Dorset. This augments and slightly updates the annotated stratigraphic log of Clements 1969. Particularly attention is given to the distribution of gastropd and ostracod faunas. The lithostratigraphic and biostratigraphic divisions of the sequence are briefly discussed.
    "1. Introduction:
    Durlston Bay is on the south side of the pleasant seaside town of Swanage which is at the eastern end of the Isle of Purbeck in Dorset, and has long been regarded as the type section of the 'Purbeckian stage'. This is the thickest, well-exposed section of the Purbeck Group in the country, and although the upper boundary (with the overlying Wealden Group) is not seen and the lower boundary (with the Portland Group) is confused by faulting and is isolated from the main part of the section, and in spite of the depredations of recent coastal defence work, there is much to be said for retaining this as the type-section of the Purbeck Group or Purbeckian facies, even though it has long since become unfashionable to speak in terms of the Purbeckian Stage. .."[continues]

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    Cobbold, P.R. and Rodrigues, N. 2007. Seepage forces, important factors in the formation of horizontal hydraulic fractures and bedding-parallel fibrous veins ('beef' and 'cone-in-cone'). Geofluids, vol. 7, 313-322.
    Bedding-parallel fibrous veins ('beef' and 'cone-in-cone') are common to a number of sedimentary basins, especially those containing black shale. The type locality is SW England. The commonest mineral in the fibres is calcite. The fibres indicate vertical opening, against the force of gravity. In the past, this has been attributed to fluid overpressure. However, a simple analysis, based on Von Terzaghi's concepts, leads to the conclusion that, for the fractures to be horizontal, either the rock must be anisotropic, or it must be subject to horizontal compression. By means of a more complete analysis, supported by physical models, we show that horizontal fractures are to be expected, even if the rock is isotropic and there are no tectonic stresses. Upward fluid flow, in response to an overpressure gradient, imparts seepage forces to all elements of the solid framework. The seepage forces counteract the weight of the rock, and even surpass it, generating a tensile effective stress. The process may lead, either to tensile hydraulic fracturing, or to dilatant shear failure. We suggest that these two failure modes, and the availability of suitable solutes, explain the frequent occurrence of 'beef' and 'cone-in-cone' respectively.

    Cobbold, P.R. and Rodrigues, N. 2013. Seepage forces, important factors in the formation of horizontal hydraulic fractures and bedding-parallel fibrous veins ("beef" and "cone-in-cone"). Marine and Petroleum Geology, vol. ? By Peter R. Cobbold and Nuno Rodrigues, Geosciences-Rennes (UMR6118), CNRS and University of Rennes 1, Campus de Beaulieu, 35042, Rennes Cedex, France.
    Principal author: peter.cobbold@univ-rennes1.fr
    Bedding-parallel fibrous veins ("beef" and "cone-in-cone") are common to a number of sedimentary basins, especially those containing black shale. The type locality is SW England. The commonest mineral in the fibres is calcite. The fibres indicate vertical opening, against the force of gravity. In the past, this has been attributed to fluid overpressure. However, a simple analysis, based on Von Terzaghi's concepts, leads to the conclusion that, for the fractures to be horizontal, either the rock must be anisotropic, or it must be subject to horizontal compression. By means of a more complete analysis, supported by physical models, we show that horizontal fractures are to be expected, even if the rock is isotropic and there are no tectonic stresses. Upward fluid flow, in response to an overpressure gradient, imparts seepage forces to all elements of the solid framework. The seepage forces counteract the weight of the rock, and even surpass it, generating a tensile effective stress. The process may lead, either to tensile hydraulic fracturing, or to dilatant shear failure. We suggest that these two failure modes, and the availability of suitable solutes, explain the frequent occurrence of "beef" and "cone-in-cone", respectively.

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    Colin , J.-P. and Oertli, H.J. 1985. Purbeckien. In: Atlas des Ostracodes de France (ed. Oertli, H.J.), Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire 9, 148-161.
    Cope , J.C.W., Ingham, J.K. and Rawson, P.F. (Editors) 1992. Atlas of Palaeogeography and Lithofacies. The Geological Society, London, Memoir No. 13. ISBN 0-903317-65-6. See Portlandian pp. 124-126 and Early Cretaceous pp. 131-133.

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    (publications by Dr. Robert Coram, mostly on fossil insects from the Purbeck Group, Dorset and related topics)

    Coram, R. and Jepson, J.E. 2012. BOOK: Fossil Insects of the Purbeck Limestone Formation of Southern England; Palaeoentomology from the Dawn of the Cretaceous. Hard-cover book, 143 pages, SSP, Siri Scientific Press, Monograph Series, Volume 3. By Robert A. Coram and James E Jepson. Edited by Dr. David Penney, Faculty of Life Sciences, University of Manchester. ISBN 978-0-9567795-3-3 With 167 figures, including many monochrome photographs and various diagrams.
    This book can be purchased directly from the publisher at:
    Siri Scientific Press, Manchester, UK.
    Example Extract from the Foreword and Acknowledgements [p.7]:
    "Although insects are the most abundant and diverse group on the planet today and presumably also in the past, their general fragility and primarily terrestrial life histories have restricted their rock (as opposed to amber) fossil record to a small number of productive sites and horizons worldwide. The Lower Cretaceous Purbeck Limestone Group of Dorset and Wiltshire in southern England is one such deposit. It provides a glimpse of insect life midway through the 'age of the dinosaurs' and shortly before the origins of the flowering plants.
    Purbeck fossil insects have been studied on and off for more than 150 years. Victorian naturalists, such as the Rev. Peter Bellinger Brodie, Prof. John O. Westward and the Rev. Osmund Fisher, collected or named numerous species. Following a comparitive lull for much of the 20th century, intensive collecting over the last two decades has resulted in the description of many new taxa and investigation of the fauna in wider palaeontological and evolutionary concepts. Thousands of Purbeck insect specimens have been collected and several hundred species described, but there is still much potential for further work.
    This book aims to give an overview of this internationally important fossil insect deposit. It begins with an introduction to Purbeck geology and palaeoenvironment and continues with observations on the taphonomy of the fossil insects. This is followed by a fully referenced list of the knownn fauna, which provides information on the 17 orders of insects recorded and an up-to-date annotated list of all the described species, along with numerous photographs and drawings. These data are then used to consider the palaeoecology of the Purbeck insects. Terrestrial and aquatic food chains are then used to consider the palaeoecology of the Purbeck insects. Terrestrial and aquatic food chains are provisionally reconstructed, the relationship between Purbeck insects and palaeonclimate is discussed and the utility of aquatic fossil insects as indicators or palaeosalinities is criticaly examined. Most recent research has focussed on the easily accessible and rapidly eroding Purbeck sections along the coast of Dorset, since the old quarry sites in Wiltshire are generally degraded. We present some observations resulting from temporary exposure of the productive Wiltshire insect bed, and then finish off with some suggestions for future research. We hope that this book will be of interest to both professional and amateur palaeontologists and entomologists and that it will form the baseline reference work for the future study of Purbeck fossil insects. "
    [this page continues with acknowledgements to follow scientists who gave comments or assistance with identification - Vladimir Blagoderov, Jane Francis, Ole Heir, Weislaw Krzeminski, Ewa Krzeminskak, John Needham, Alexandr Rasnitsyn and other...]


    Coram, R.A. 2003. Taphonomy and ecology of Purbeck fossil insects. Acta Zoologica Cracoviensia, 46, Supplement: Fossil Insects, pp. 311-318. By Dr. Robert Coram. Purbeck fossil insect specialist of Dorset, England.

    Coram , R.A. 2003. Taphonomy and ecology of Purbeck fossil insects. Acta Zoologicica Cracoviensia, 46 (supplement - Fossil Insects), 311-318, Krakow, 15 October, 2003. Accepted for publication: 2002. By Robert A. Coram of Swanage, Dorset, UK.
    Abstract. The basal Cretaceous Purbeck Limestone Group of southern England yields many fossil insects and study of their taphonomy allows a preliminary reconstruction of their life habitats. The aquatic fauna comprises a low diversity brackish water assemblage as well as transported remains of probably fresher water taxa. The terrestrial fauna comprises largely woodland inhabitants that generally became disarticulated prior to arrival at the site of deposition. [end of abstract].
    Example extract from text:
    1. Introduction and Geological Background:
    The Purbeck Limestone Group, best exposed in Dorset, southern England, consists mainly of lagoonal sediments currently considered to be basal Cretaceous (Berriasian) in age (Allen and Wimbledon, 1991). Fossil insects are found at many horizons and can be very abundant, occurring in their hundreds on some bedding planes. They can be found at many coastal and inland quarry localities in Dorset, but the majority have come from the Purbeck type section at Durlston Bay, near Swanage (National Grid Reference SZ 035780), which is still productive (Fig. 1). Seventeen orders of Purbeck insects have been recognised and about 200 species have been described, although a far greater number await description (Coram and Jarzembowski, 2002). This paper is a preliminary attempt to divide the Purbeck insect fauna into broad environmental categories on the basis of their taphonomy and to make some taphonomic comparisons with other deposits of similar age. The Purbeck Limestone Group is divided into a lower Lulworth and upper Durlston formations. It is underlain by limestones of the Tithonian (Upper Jurassic) Portland Limestone Group containing a normal marine fauna, including giant ammonites, and is succeeded by non-marine, predominantly fluvial, deposits of the Wealden Group extending to the Upper Barremianl earliest Aptian. These are also insectiferous (Jarzembowski, 1984), providing the opportunity to track changes in the insect fauna through much of the Lower Cretaceous in southern England... [continues with a map of Dorset outcrops, three photographs of slabs with insects, a diagram showing ordinal representation of insect fossils in the Corbula Beds, and a good full-page diagram of the inferred life habitats of various Purbeck insects (dragonfly nymphs and chironomids in the brackish lagoon; beetles and cockroaches on the shell beach or sabkha; bugs and fly larvae in the freshwater lake; crane flies, gnats and midges in the damp forest; orthoptera in the open glades; snake flies, fungus gnats, cupedid beetles, buprestid beetles, aphids and plant bugs in the forested land).]

    Coram, R. 2009. Purbeck Fossil Insects; Weymouth Relief Road, Bincombe. 10 pp. pdf file, May 2009 by Dr. Robert Coram. Extract: "In May 2009 excavations for the Weymouth Relief Road at Bincombe exposed a Purbeck section displaying both of Fisher's insect beds. Along with Ed and Biddy Jarzembowski, I had the opportunity to visit the site and collect insect specimens. The upper of Fisher's beds yielded a small amount of material; his Lower Insect Bed, near the base of the Purbeck, proved much more productive. A selection of specimens from this horizon are shown on the next few pages, followed by comments on the likely palaeoenvironment." [Remains of Trichoptera (Caddis Flies), Neuroptera (Lacewings), Coleoptera (Beetles), Orthoptera (Grasshopers and Crickets), Odonata (Dragonflies and Damselflies), Hemiptera (Bugs), Diptera (True Flies), Blattodia (Cockroaches) and Mecoptera (Scorpion Flies) have recorded by Robert Coram and many are illustrated in photographs.]

    Coram, R.A. and Jarzembowski, E.A. 1999. New fossil flies (Insecta : Diptera) from the Purbeck Limestone Group (Lower Cretaceous, Berriasian) of Dorset, UK. Cretaceous Research, 20, 853-861. Abstract: Two new species from small, exclusively Mesozoic, families of nematoceran Diptera (true flies) from the Purbeck Limestone Group (Berriasian) of Dorset, UK are described, namely Procramptonomyia zigzagensis sp. nov. (Procramptonomyiidae) and Ellia purbeckensis sp. nov. (Elliidae). The fossil evidence suggests that these two families, along with the extant Cramptonomyiidae, are closely related.

    Coram, R.A. and Jarzembowski, E.A. 2002. Diversity and ecology of fossil insects in the Dorset Purbeck succession, southern England. By Robert A. Coram, Swanage, and Edmund A. Jarzembowski, Maidstone Museum and Reading University. Special Papers in Palaeontology, 68, 257-268. Abstract:Purbeck fossil insects have been collected and studied for more than 140 years, and have recently seen a revival of interest. Their remains occur in many Lower and Middle Purbeck horizons and can be very abundant. The use of species accumulation curves suggests that there are about 1400 fossil insect species in the Dorset Purbeck, although this is probably an underestimate of true diversity. At ordinal level the insect fauna is much more similar to that of the Recent than the Permian, although lacking important Recent groups such as the butterflies and moths (Lepidoptera) and social ants, bees and wasps (Hymenoptera). A low diversity aquatic insect assemblage can be recognized and could be used as a guide to palaeosalinity. The insect data broadly support the evidence for a 'Mediterranean' climate for southern England during the Early Cretaceous.

    Coram, R., Jarzembowski, E.A. and Ross, A.J. 1995. New records of Purbeck fossil insects. Proceedings of the Dorset Natural History and Archaeological Society, for 1994, 116, 146-150.

    Coram, R. and Jarzembowski, E. A. 1998. Insect-bearing horizons in the type Purbeck and new Purbeck/Wealden flies (Diptera). Proceedings of the Dorset Natural History and Archaeological Society, 119 (for 1997), 135-140.

    Coram, R.A. and Jarzembowski, E.A. (in press). Diversity and ecology of fossil insects in the Dorset Purbeck. In: Symposium, Life and Environments in Purbeck Times, Dorchester, Dorset, 19th-22nd March, 1999.

    Coram, R., Jarzembowski, E. A and Mostovski, M. B. 2000. Two Rare Eremoneuran Flies (Diptera: Empididae and Opetiidae) from the Purbeck Limestone Group. Paleontological Journal, 34 (Supplement 3), S370-S373.


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    Cosgrove , M.E. and Hearn, E.W. 1966. Structures in the Upper Purbeck Beds at Peveril Point, Swanage, Dorset. Geological Magazine, vol. 103, No.6, 498-507. [I introduced the authors to this locality, after some initial studies and mapping. They advanced the work, using, amongst other things, step-ladders at low tide. By the late Dr. Michael Cosgrove and by Edward Hearn]


    Damon, Robert,

    Robert Damon, 1814-1899, was a well-known Dorset geologist and collector of and dealer in fossils. He was born in Weymouth, with origins in a Flemish family. He ran a fossil shop at Augusta Place, the Esplanade, Weymouth. This shop is now a fish and chip shop (information kindly provided by his great, great grandaughter - Carole Burridge - nee Carole Damon, who lives in Bridport). Robert Damon was a Member of the Imperial Natural History Society of Moscow, and visited Russia in 1883, bringing back samples. His books are extremely interesting, with many diverse footnotes and sidelines. Robert Damon made a private collection of 400 Dorset fossils to illustrate his books. The Victoria Museum, Australia has ichthyosaurs from Damon, and many other museums contain fossils of his.

    Damon , R. 1860. Handbook to the Geology of Weymouth and the Isle of Portland; with Notes on the Natural History of the Coast and Neighbourhood. By Robert Damon. Accompanied by a map of the district, geological sections, plates of fossils, coast views, and numerous other illustrations. London, Edward Stanton, 6 Charing Cross, 1860. This edition is available online in Google Book Search. The second edition, listed below is mostly the same but with some additions.

    Damon , R. 1884. Geology of Weymouth, Portland, and Coast of Dorsetshire, from Swanage to Bridport-on-the-Sea: with Natural History and Archaeological Notes. New and Enlarged Edition (2nd Ed.), Weymouth, R.F. Damon, London, Edward Stanford. 250p. With a colour geological map of part of the Dorset coast, and including a log of the Purbeck strata of Durlston Bay, Swanage, by H. W. Bristow and Prof. E. Forbes (although note that it contains a small error). (A copy of Damon's second edition is in the possession of Ian West)
    Preface to Second Edition
    Since the issue of the First Edition increased attention has been given to the Geology of the coast of Dorsetshire, especially in the contributions of Messrs. Blake and Hudleston, and Professor Prestwich, which in part have been embodied in the present volume.
    Elementary and explanatory notes are given for the use of those young in the study of the science.
    A description of the geological formations of Swanage and Bridport, the two extremes of the district under consideration, is for more convenient reference placed towards the end.
    The Geological Survey of this district was almost entirely made by Mr. Henry W. Bristow, Senior Director of the Geological Survey of Great Britain. To him I am greatly indepted for a final revision of the work. Mr. W. Topley, of the Survey, has also kindly given much assistance, as have also Messrs. G. Sharman and E. T. Newton with the lists of fossils. Mr. Etheridge has favoured me with the Bridport portion of his unpublished sections of the Oolitic rocks of England.
    The works I have consulted are necessarily very numerous, and to their respective authors I acknowledge my great obligations.
    To the above and other friends, who have kindly responded to my enquiries for information, my sincere thanks are rendered.
    R. Damon
    Weymouth, October 1884.
    Davey , I. and Morcombe, M. 1972. Australia: Colourful Continent. Rigby, Adelaide. 126pp. [re salt lake illustration]
    Davies , W. 1887. On new species of Pholidophorus from the Purbeck Beds of Dorset. Geological Magazine, (3), vol. 4, 337-339.
    Delair, J.B. 2005. Some highlights of the fossil collections of the Bournemouth Natural Science Society: series 3: vertebrata. Proceedings of Bournemouth Natural Science Society, vol. 66 (2), pp. 40-45. By Justin Delair. [Report of plesiosaur remains from the Purbeck Group of Dorset.]

    Deconinck, J-F, Baudin, F. and Tribovillard, N. 2000. The Purbeckian facies of the Boulonnais: a tsunami deposit hypothesis (Jurassic-Cretaceous boundary, northern France). Comptes Rendus Acad. Sci. Paris, Science de la Terre et des planetes; Earth and Planetary Science, 330 (2000), 527-532. By Jean-Francois Deconinck, Francois Baudin and Nicholas Tribovillard.
    Abstract: We consider the origin of the Purbeckian deposits (Uppermost Jurassic - Lowermost Cretaceous) in the Boulonnais. Made up of an erosional conglomerate overlain by wood fragments and clays containing continental and marine fossils, they are attributed to a tsunami triggered either by an earthquake or the impact of a bolide in the palaeo-Barents Sea.
    [Purbeck deposits in the cliffs between Wimereux and Pointe aux Oies, north of Boulogne-sur-Mer, Channel coast, northern France. Charophytes and stromatolites are present in the cliff sections. There is uncertainty regarding the exact age. There is a conglomerate known as the Poudingue de la Rochette, and this contains pebbles of Devonian, Carboniferous and Jurassic rocks of the Boulonnais area. (note incidently that there is a bed within the Unio Member, Upper Purbeck of Stair Hole, Lulworth Cove, Dorset that shows liquifaction, probably as a result of earthquake origin. This is not discussed in the paper and may not be of relevance; it probably relates to local Dorset tectonism.) ]

    Deconinck, J-F. and Strasser, A. 1987. Sedimentology, clay mineralogy and depositional environment of Purbeckian green marls (Swiss and French Jura). Eclogae Geological Helv. ,80, 753-772.

    Deconinck , J.F., Strasser, A. and Debrabant, P. 1988. Formation of illitic minerals at surface temperatures in Purbeckian sediments (Lower Berriasian, Swiss and French Jura). Clay Minerals, 23. 91-103. Abstract: The clay-mineralogical assemblage of Purbeckian carbonate sediments of the Swiss and French Jura Mountains are often composed of illite and interstratified illite-smectite. These illitic minerals occur mainly in thin layers of green marls which show evidence of subaerial exposure and mark the top of the shallowing upward sequences. X-ray diffraction, chemical and thermal analyses coupled with transmission electron microscopy suggest that the Purbeckian illitic minerals replaced smectite in intermediate continental-marine environments. The transition from smectite to illite and interstratified illite-smectite probably resulted from repeated cycles of wetting by marine waters and subsequent drying in hypersaline environments, under a hot Purbeckian climate.
    Delair , J.B. 1982. Multiple dinosaur trackways from the Isle of Purbeck. Proceedings of the Dorset Natural History and Archaeological Society, vol. 102 for 1980, 65-67. [ Brief discussion of dinosaur footprints at three sites in the Isle of Purbeck. These are of theropod type from the Middle Purbeck of Lock's Quarry, Langton Matravers (although listed as Acton on some photographs), of Iguanodont type from Worbarrow Tout and wrongly recorded as Lower Purbeck but actually Middle Purbeck above the Cinder Bed, and of Iguanodont type from a quarry at Queensground, Acton, near Swanage. The Lock's Quarry set were brought to Delair's attention by the late Mr E. Oppe. The footprints occurred in the Pink Bed of the Roach of the Intermarine Member. Part of the trackways were acquired by the Royal Scottish Museum, Edinburgh and were put on display. Two trackways were found with a total of about 31 prints and the tracks crossed over at two points. The anterior-posterior measurement of individual prints averaged 28 cm in one track and 34 cm in the other. Measurements of the spacings of the footprints are given in a plan of the site.

    Delair, J.B. 1985. Some little known Jurassic Ichthyosaurs from Dorset. Proceedings of the Dorset Natural History and Archaeological Society, 107: 127-134.

    Delair, J.B. and Brown, P.A. 1975. Worbarrow Bay Footprints. Proceedings of the Dorset Natural History and Archaeological Society, vol. 96 for 1974, 14-16.
    Extract (most of the paper):
    "In 1888, Mansel-Pleydell (5, p.36) mentioned the occurrence of footpints with dissociated Iguanodon remains in the Wealden formation at Worbarrow Bay. This appears to be the only published record of reptilian footprints of any age at Worbarrow. [In fact, though, these footprints had already been reported briefly reported by West et al. and had been well-known for a long time and regularly pointed out on field trips. As a result of such a trip they are also shown in Kirkaldy, J.F. 1970. Fossil in Colour. Blandford Press, see p. 48.]
    Although the present writers have failed to locate Mansel-Pleydell's specimens (which, of course, may actually have never been collected), it appears certain that they were of the three-toed or tridactyle variety since, in Mansel-Pleydell's day, only footprints of that kind were assigned to Iguanodon. More recently the essentially identical tridactyle dinosaurian footprints I present at certain subjacent Purbeck horizons have been separated into two distinct groups, ascribed respectively to Iguanodont and Megalosaurian dinosaurs (7, figs. 1 and 2). It is unknown, therefore, whether Mansel-Pleydell's Worbarrow Bay footprints were of Iguanodont or Megalosaurian type, even though we may be sure that they were of dinosaurian origin.
    There are, however, no reasons to doubt that Mansel-Pleydell's Worbarrow specimens really were from Wealdon [sic] beds (which outcrop on the northern side of the bay), since elsewhere he specifically mentions two footprint-bearing sandstones in the Wealden formation at Swanage Bay (6, p.117), and clearly distinguished the Wealden from the Purbeck beds at those localities. The footprint-bearing sandstones of Swanage Bay had, in fact, been recorded as far back as 1862 (2, p.446), and presumably it was to the specimens found at that early date that Mansel-Pleydell referred. There appears to be no published record of exactly when the Worbarrow Bay footprints were discovered and examined, although their discovery obviously antedated 1888.
    Somewhat oblique confirmation of the general accuracy of Mansel-Pleydell's dating of these early footprint discoveries is contained in the obituary of the late Frank Raw (died 2nd September, 1961), which mentions the discovery many years later of at least one further tridactyle footprint in the Wealden strata at Swanage Bay (8, p.159). The recent discovery, therefore, of several trackways composed of tridactyle footprints in the basal Purbeck beds at Worbarrow Bay (fig. l) constitutes a new record for footprints of that age in Dorset, and is a find of considerable interest.
    The present specimens (uncollected) were examined in situ during late September 1973 by the writers, shortly after one of them (PAB) had learned of their existence by chance. As photography of the specimens was not possible (due principally to their awkward location and to indifferent lighting conditions at the time) the arrangement of the footprints, relative one to another, is shown in fig.2.
    With the exception of a single additional footprint found on a block obviously fallen from some higher level, and collected by PAB, all the footprints occur as impressions on the upper surface of a black-speckled limestone tilted downwards towards the north at an angle of approximately 55 degrees and towards the west at an angle of about 25 degrees. Stratigraphically, the position of this bed is difficult to correlate precisely with those of other Purbeck sections in this district, but appears to equate with bed no:6 in Arkell's summary of the basal Purbeck series on the east side of "Worbarrow Tout" (1, pp. 301-2). This correlation, however, is provisional only as the precise age of the Purbeck beds in the Worbarrow Bay area, and especially those north of the "Tout", has recently been queried (4, p.567).
    The single detached specimen mentioned above appears to have fallen from the Cypris Freestones or from the Broken Bed underlying them (1, pp.301-2, see beds 12 and 13 in the published section).
    As shown in fig.2, the footprints form three separate trackways, all aligned in a general north-easterly direction. Measured between the two out digits, the width of each specimen, which in some cases is rather indistinctly defined, is approximately 7 inches. That of the detached footprint from the higher horizon is approximately 8 inches, and, like those of the trackways is of Iguanodont type.
    The stratigraphical position of these footprints is of particular interest, inasmuch that it apparently lies in or near the basal Purbeck series [This is in error - the footprints are from above the Cinder Bed!], and occurs much lower down than the main and, to date, much more productive footprint-bearing horizons the Middle Purbeck series of the Swanage district further east (3, see fig. 2) [not true]. The reported existence of tridactyle reptilian, footprints in the lower Purbecks has, however, been known for many years (6, p.122) [?]. Of additional interest is the fact that even at the present low [sic] horizon, footprints of a general Iguanodont type occur .. at least in the Worbarrow Bay region .. in relative abundance, a circumstance which has hitherto passed unnoticed [it has not!].
    Our best thanks are due to the army authorities at Lulworth Camp for permission to visit Worbarrow Bay which, with the neighbouring area, lies within the military testing grounds.
    APPENDIX Further to the stratigraphical distribution of dinosaur footprints in the Dorset Purbeck formation summarized by Delair and Lander in 1973 (3, fig.2), it is, perhaps, appropriate here to add the following supplementary details that have come to light since the publication of that paper, since, together with the Worbarrow Bay discovery detailed above, they constitute notable additions to the record.
    At least one well preserved cast of a typical Iguanodont footprint has recently been recovered from the "Soft Burr" bed in 'Marble Quarry' north of Langton-Matravers, while several additional similar casts have been collected from the "Roach" stone at 'Worth Gate Quarry', near Acton.
    All these trace-fossils are now owned by Mr David Sole of Langton-Matravers, to whom we are indebted for the opportunity of examining them.
    On March 3rd, 1967, Mr Geoffrey Tyers, from Nottingham, found another Iguanodont footprint in a limestone block on the foreshore at Peveril Point, Swanage. Almost certainly the block had fallen from an Upper Purbeck horizon (as yet undetermined) in the adjacent cliffs. This specimen, which is now owned by a Mr E. Fuller, is of considerable interest in the footprints of Upper Purbeck age are encountered only rarely. Indeed, only Mansel-Pleydell has recorded the definite occurrence of dinosaurian footprints from the Upper Purbeck beds of Dorset (6, p.122), even though it seems that the specimens upon which that record was based are now lost.
    Our grateful thanks are due to Prof. W.A.S. Sarjeant of Saskatchewan University, Calgary, for bringing this latter discovery to our attention.
    P.A. Brown, Corfe Castle, Dorset.
    J.B. Delair, Wootton, Berkshire.
    1st October, 1973 (Revised, 21st February, 1974)."
    [With fig. 1, location map of Worbarrow Bay and Tout and fig. 2, a drawing of the footprints. Also with 8 references.]

    Delair, J.B. and Lander, A.B. 1973. A short history of the discovery of reptilian footprints in the Purbeck Beds of Dorset with notes on their stratigraphical distribution. Proceedings of the Dorset Natural History and Archaeological Society, vol. 94 for 1972, 17-20.

    Delair.J. B. and Sarjeant, W.A.S. 1985. History and Bibliography of the Study of Fossil Vertebrate Footprints in the British Isles: Supplement 1973-1983. Palaeogeography, Palaeoclimatology, Palaeoecology, 49: 123-160.
    Decisneros, C.J. and Vera, J.A. 1993. Milankovitch cyclicity in Purbeck peritidal limestones of the Prebetic (Berriasian, southern Spain). Sedimentology, 40, 513-537. Abstract: Peritidal carbonate rocks (Purbeck facies) of the uppermost Portlandian to Berriasian in the type section of the Sierra del Pozo Formation in the Prebetic Zone, southern Spain, are divisible into 141 shallowing upward cycles averaging 2 m in thickness. The subtidal facies in these cycles consist of micritic or marly limestones with dasycladacean algae and lituolids; the intertidal facies are micritic limestones containing birdseyes and miliolids; the supratidal facies comprise laminated algal limestones, the tops of which display desiccation cracks and rhizocretions, or more locally palaeosols, calcretes, or palaeokarst surfaces. A statistical study, using power spectra of the Fast Fourier Transform, demonstrates that the periodicity of these cycles is in the Milankovitch frequency band. Most sedimentary cycles correspond to the obliquity cycles; eccentricity and precession cycles have also been recognized. Using a Fischer plot, third-order tectono-eustatic cycles are recognized, which can be correlated with the eustatic curve of the Exxon chart. The shallowing upward sequences are characterized by a distinctive pattern of geochemical parameters. Carbon and oxygen isotopic (deltaC-13 and deltaO-18) variations, calcium and magnesium carbonate contents and the abundance of organic matter and trace elements (Mn and Sr) all have predictable patterns of distribution within the sequences. The Sr content of the subtidal facies is relatively high whereas the deltaC-13 and deltaO-18 ratios are quite low; in the intertidal facies the Sr and Mn levels fall concomitantly with a rise in deltaC-13 and deltaO-18. The highest deltaC-13 and deltaO-18 values occur in the lower part of the supratidal facies, whereas in the upper part of delta values and Sr contents drop sharply. Cyclic variations in evaporation and in meteoric water influence, determined from oxygen isotopic composition, reveal that the cyclicity of the beds containing the most limestones (supratidal) and those with the most marls (subtidal) is related to climatic changes. The coldest periods are those represented by supratidal deposits, when the sea level was at its lowest. During the warmest periods, when the overall sea level was higher, subtidal deposits accumulated in the region. A genetic model is proposed, according to which the asymmetrical sedimentary cycles occur in response to glacio-eustatic changes with a periodicity similar to that of Plio-Pleistocene sea-level variations, but with a much lower range due to the smaller extent of polar ice caps during the Early Cretaceous. The glacio-eustatic changes involved a rapid sea-level rise and a slow sea-level fall.
    D'El-Ray Silva , L.J.H.D. 2001 (or Silva 2001?- I am not sure which is correct). Structures in Jurassic rocks of the Wessex Basin, southern England - II diapirism in evaporite layers. By Luiz Jose Homem D'El-Ray Silva. [On mushroom structure in the Purbeck Broken Beds].Revista Brasileira de Geociencias, 31(l):75-82, March 2001. Universidade de Brasilia - Institute de Geociencias - Campus Universitario, Asa Norte, 70.910-900, Brasilia, DF, Brazil - e-mail: ldel-rey@unb.br.

    This paper should not be taken seriously because the famous Purbeck stromatolites or thrombolites surrounding the remains of fossil trees at the Fossil Forest are described within it as evaporitic diapers! This is not a minor error: the paper is so erroneous and with such neglect of previous literature that it should not have been published in a serious journal.

    Go to Silva (2001) where the abstract and more detail is given. Complete paper is available on the internet free as a PDF file, or search with Google.

    Diesing, M., Coggan, R., and Vanstaen, K. 2009. Widespread rocky reef occurrence in the central English Channel and the implications for predictive habitat mapping. Estuarine, Coastal and Shelf Science, (Accepted Manuscript 19th May 2009, available online 28th May 2009). By Markus Diesing, Corresponding Author, Roger Coggan and Koen Vanstaen, Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk, NR33 0HT, United Kingdom. Email address given for corresponding author - markus.diesing@cefas.co.uk.
    Reefs are one of the marine habitats listed in Annex I of the European Union's Habitats Directive, which aims to establish a coherent European ecological network of special areas of conservation. EU Member States are required to prepare and propose a national list of sites for evaluation under the scheme, but currently the occurrence of reefs in the United Kingdom's nearshore and offshore areas is not well documented. Here we report on our search for rocky reefs in the central English Channel, which unexpectedly revealed an extensive reef system covering an area of 1100 km2. Prior to our work, it was generally perceived that the seabed in this area comprised mostly gravel, with a few isolated rock outcrops.
    Our approach to determining the location, extent and character of these reefs incorporated broad, medium and finescale analyses over a 3200 km2 area of seabed, using single- and multi-beam acoustic data, ground-truthed by underwater video and stills imagery. A benthic terrain model was developed in ArcGIS to map topographic features at the broad and medium scales. Biotope assignments were made at the fine scale through detailed analysis of video footage obtained from 30 sampling stations. The study area has a complex geological history and lies at the centre of a major bedload parting zone. Together, these strongly influence the seabed character and the distribution of biotopes. An integrated assessment of the physical and biological features was used to map the study area to level 4 of the EUNIS habitat classification system.
    Similar physical conditions exist in other areas of the UK continental shelf, raising the prospect of predicting where other rocky reef systems might occur. In the absence of a co-ordinated national seabed survey programme, such predictions, coupled with interpretation of existing single-beam bathymetry data, can help prioritise areas where limited survey resources could be most effectively deployed.
    [Reefs are Lower Cretaceous, predominantly sandstones, shales, mudstones and siltstones of the Wealden Group. Not specifically on the Purbeck Group. Shows palaeovalley south of the Isle of Wight in some detail]
    DIGS , 2009. The Purbeck Limestone Group: Virtual geology field trips to Purbeck limestone quarries in south Dorset. CD available to teachers etc.

    Presented by DIGS - Dorset's Important Geological Sites Group. Supported by the Purbeck Keystone Project, and Lottery Funded. The project has involved creating a virtual geology field trip, on a CD, to the Purbeck Limestone Quarries. This is being made available to teachers, lecturers, students and outdoor education centres. The CD has very high quality photographs, colour diagrams and information. It is in the format of PowerPoint presentations, that are very clear and are very well-organised.

    Contents: The PowerPoint Presentations
    1. Read me before launching
    2. Introduction
    3. A short history of the Purbeck quarrying industry
    4. Portesham Quarry
    5. Swanworth Quarry
    6. California Farm Quarry
    7. Keates' Quarry
    8. Queensground Quarry
    9. Crack Lane Quarry
    10. The Purbeck palaeo-environment

    About D.I.G.S. [information from the cover of the CD]
    Dorset's Important Geological Sites Group (D.I.G.S.) is a volunteer organisation whose aims are the registration and preservation of important geological exposures throughout the county. Currently over 60 sites are registered as regionally important sites which are of educational value but which would otherwise be unprotected from development. An aim of the organisation is to raise awareness of Dorset's geological heritage by means of field trips, guided walks, lectures and the publication of field guides and booklets.
    For further information on publications and membership please contact:
    D.I.G.S., clo Dorset Wildlife Trust, Brooklands Farm, Forston, Dorchester DT2 7 AA.

    The Keystone Project
    The Purbeck Keystone Project is a 3 year project funded by the Heritage Lottery Fund. The main aim of the project is to support farming, stoneworking and outdoor education in the Isle of Purbeck. The aim of the project in partnership with Dorset's Important Geological Sites Group is to provide safe physical and intellectual access to the geology of the Isle of Purbeck.
    Donovan , D.T. and Stride, A.H. 1961. An acoustic study of the sea floor south of Dorset and its geological interpretation. Philosophical Transactions of the Royal Society, B, 244, 299-330 [maps of the Purbeck outcrop on the sea floor].
    Drury , G.D. 1948. The use of Purbeck Marble in mediaeval times. Proceedings of the Dorset Natural History and Archaeological Society, 70, 74-98. With 28 monochrome plates, mostly photographs of tombs, pillars and fonts in Purbeck Marble. By G. Dru Drury, M.R.C.S., L.R.C.P., F.S.A. (Read 30 November, 1948). "The subject has been well written up in the Victoria County History of Dorset (Vol. 2, p. 331), and prior to this, Hutchins (History of Dorset, Vol. 1, p. 466 et seq.) gave much useful information, including extracts from the Sheriff's accounts for Dorset regarding the supply and destination of worked marble, particularly in the reign of Henry III. .. Purbeck marble inevitably figures largely in the numerous works on mediaeval architecture and sculpture, predominantly ecclesiastical in the case of the former and particularly monumental in regard to the latter. It is by no means easy to contribute anything original to the very considerable amount of evidence already at out disposal. ..There is enough material to make a book dealing solely with this large and fascinating subject, but much of it is accessible only in reference libraries, and the first object of this paper is to assemble these records in a convenient and condensed form, adding some personal observations which are the result of the pursuit of Purbeck marble over a number of years. Secondly, it is an endeavour to answer, in some measure, the following questions which are so frequently asked.
    A. Was the marble carved at the site of the quarries or elsewhere; to what extent was it finished locally?
    B. What was the cause of its rapid rise in popularity during the 13th century, with such an enormous output that it is to be found in the structure or fittings of most of the important ecclesiastical buildings of the Early English and the Decorated periods in the country?
    C. Why did its use decline and gradually fade out after reaching its peak in the middle of the 14th century?
    General Considerations:
    The relatively thin vein of marble occupies a line about halfway down the northern slope of the southern range of the Purbeck Hills between Peveril Point and Warbarrow Tout. It is easy of access from the surface owing to the tilting of all the Purbeck strata, but extraction from the lower levels is a very laborious undertaking. The yield of good workable material only amounts to about eighteen inches to two feet in thickness, and it is due to this circumstance that the Purbeck marble effigies show a distinct flatness in rendering which gives them a characteristic style. There is considerable variation both in colour and in quality, the reddish variety is far the most durable, and unlike the other hues, can stand exposure to the weather quite well...Tumbled remains of the mediaeval surface quarries, now overgrown, can be seen at various points, notably at Wilkeswood; at Quarr; at Dunshay whence came the marble for Salisbury Cathedral, the drive leading to Dunshay manor house winds right through the old marble workings; at Woodyhyde, where the quarries were reoppened in 1842 to provide marble for the restoration of the Temple Church, London; at Scoles; at Afflington where there was once a flourishing village in connection with the marble and stone industries and to which Henry III granted a market and a fair in 1270; at Lynch; and at Blashenwell, where the quarries were used as late as the year 1880 by G.E. Street when he built the near-by new church at Kingston." ... (continues)


    Dyke, G.J., Benton, M.J., Posmosanu, E. and Naish, D.W. 2011. Early Cretaceous (Berriasian) birds and pterosaurs from the Cornet Bauxite mine, Romania. Palaeontology 54: 79-95.
    By: Dyke, Gareth J., Benton, Michael J., Posmosanu, Erika and Naish, Darren (2011). Dr. Gareth Dyke is now at Ocean and Earth Science, National Oceanography Centre, Southampton University.

    We revisit a small but extremely significant collection of bird and pterosaur bones from the Lower Cretaceous (Berriasian) of western Romania. These fossils were collected in the late 1970s and early 1980s from a Lower Cretaceous (Berriasian) conglomerate lens deep in a bauxite mine at Cornet, close to the city of Oradea, Romania, and they caused a sensation when first described. Some fossils were initially ascribed to the early bird genus Archaeopteryx as well as to the modern clade Neornithes, an astonishing avian assemblage if correct. Described pterosaurs include dsungaripterids and a cervical vertebra that is likely the oldest azhdarchid pterosaur known from Europe and perhaps the world. Not only does the Cornet azhdarchid support an Eurasian origin for this clade, it is also significant because of its size: it is one of the smallest representatives of this pterosaur clade yet reported. Aside from their phylogenetic affinities, these unique Romanian fossils are also important because of their age; in particular, very few birds are known globally from the earliest Cretaceous. Re-examination of collections in Oradea confirms the presence of both birds and pterosaurs in the Cornet bauxite: although the fragmentary bird remains are mostly indeterminate, one record of a hesperornithiform is confirmed. There is no evidence for Archaeopteryx at the Cornet site while the two supposed neornithines (Palaeocursornis biharicus Kessler and Jurcsak and Eurolimnornis corneti Kessler and Jurcsák) are based on undiagnostic remains and are here regarded as nomina dubia.

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    Dypvic, H. and Attrep, M. Jr. 1999. Geochemical signals of the Late Jurassic Mjolnir impact. Meteorics and Planetary Science, vol. 34, 393-406.

    Dypvic, H., Gudlaugsson, S.T., Tsikalas, F., Attrep, M. Jr., Ferrell Jr. R.E., Krinsley, D.H., Mork, A. Faleide, J.L., Nagy, J. 1996. Mjolnir structure: an impact crater in the Barents Sea. Geology, 24, 779-782.
    A systematic search for impact indicators was conducted on a core of Late Jurassic-Early Cretaceous sedimentary strata from the vicinity of the proposed Mjolnir impact structure, Barents Sea. A 0.8-m-thick section of the core was found to contain unequivocal indicators of meteoritic impact: shocked quartz grains and a strong enrichment in iridium. The ejecta-bearing strata were discovered only 30 km north-northeast of the structure, within a stratigraphic interval corresponding to the seismically defined deformation event at Mjolnir. Further study of this unusually well preserved impact-crater-ejecta-layer pair may help constrain poorly understood aspects of large-magnitude meteorite impacts into the oceans.
    Edmonds, R. 2008. Exceptional fossils from the Intermarine Member, Purbeck Limestone Group, early Cretaceous, Durlston Bay, Swanage, Dorset: implications for our attitudes to collecting. Proceedings of the Dorset Natural History and Archaeological Society, 129, 2008, 217-219. By Richard Edmonds of Jurassic Coast. [Crocodile skull discovered etc.]
    El-Shahat , A. l977. Petrography and Geochemistry of a Limestone Shale Sequence with Early and Late Lithification: the Middle Purbeck of Dorset, England. Unpublished Ph.D.Thesis , University of Southampton. 295 pp. [detailed thin-section petrography ,trace-element geochemistry, and clay mineralogy of the Purbeck type section of Durlston Bay]

    El-Shahat, A. and West, I.M. 1983. Early and late lithification of some aragonitic bivalve beds in the Purbeck Group (Upper Jurassic - Lower Cretaceous) of southern England. Sedimentary Geology, 35, l5-4l. Abstract: Beds of euryhaline bivalves alternating with shales constitute much of the middle Purbeck Group. They originated on "tidal" flats at the western margin of an extensive brackish lagoon. When these shell beds are thin and enclosed in shale they are often still preserved as aragonite and associated with "beef", fibrous calcite formed during compaction. In most cases, however, the shell debris has been converted into calcitic biosparrudite limestones. A compacted type has been lithified at a late stage, after deep burial. In this, pyrite is abundant and most of the shell aragonite has been replaced neomorphically by ferroan pseudopleochroic calcite. A contrasting uncompacted type of biosparrudite is characterised by bivalve fragments with micrite envelopes. Shells and former pores are occupied by non-ferroan sparry calcite cement, and there is little pyrite. These limestones frequently contain dinosaur footprints and originated in "supratidal" environments where they were cemented early, mainly in meteoric water. Once lithified they were unaffected by compaction. This uncompacted type indicates phases of mild uplift or halts in subsidence. These shell-bed lithologies, and also intermediate types described here, will probably be recognised in other lagoonal formations.
    Elstner , F. and Mutterlose, J. 1996. The Lower Cretaceous (Berriasian and Valanginian) in NW Germany. Cretaceous Research, vol. 17, pp. 119-133. Abstract: The non-marine sedimentary successions of the Berriasian and lower Valanginian of NW Germany are described. The stratigraphical distribution of ostracods allow this interval to be subdivided into 10 biozones, which can be used for regional correlation in the central part of the NW German Basin. Three ostracod taxa (Fabanella ansata, Cypridea alta formosa and Pachycytheridea compacta) can be used for interregional correlation between Germany, Denmark, France and England. The middle parr of the Katzberg Member, which yields F. ansata, allows correlation with the Lower Purbeck of S England, the Paris Basin, and the Boulonnais. The first occurrence of this species can be used to define the Portland/Purbeck boundary. Fluctuations in the taxonomic content of ostracod assemblages reflect changes in salinity. Brackish conditions dominated deposition during the earliest Berriasian (Munder Formation) and earliest Valanginian (Osterwald Member). Sediments of the late Berriasian Obernkirchen Member were deposited under freshwater conditions. A short-lived marine transgression marked the mid Berriasian (base Wealden 4). The Platylenticeras Beds of mid-Valanginian age indicate a return to fully marine conditions.

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    Emerton, S., Muxworthy, A.R. and Sephton, M. A. 2013. A magnetic solution to the Mupe Bay mystery. Marine and Petroleum Geology, vol. 46, pp. 165-172. September 2013. By Stacey Emmerton, Adrian R. Muxworthy and Mark A. Sephton. Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
    [This is an important paper regarding oil migration in the Wessex Basin!]

    • The clasts hold a magnetic signal unlike the matrix indicating two phase staining.
    • The clasts show similar directions and thus were soft when deposited into the bed.
    • The clasts indicate the onset of oil migration in the Early Cretaceous.
    • The matrix is consistent with today's magnetic field and is an active oil seep.

    An outcrop of Wealden beds at Mupe Bay (UK) is associated with a key piece of evidence for the timing of hydrocarbon migration in the Wessex Basin. A conglomeratic bed contains oil-stained clasts and matrix that appear different upon superficial observation. Conventional interpretations assign differences to the erosion and transport of oil-cemented clasts by Wealden rivers before their incorporation into a later stained conglomeratic bed. This scenario constrains the onset of oil migration in the basin to the Early Cretaceous; however, arguments have been put forward for single phase staining.
    Magnetic information may provide new ways to examine the Mupe Bay record of oil migration. Migrating fluids such as hydrocarbons have been shown to cause chemical conditions suitable for the alteration or formation of authigenic magnetite resulting in associated chemical remanent magnetization (CRM). Magnetic characterization reveals both the matrix and clasts contain multi-domain magnetite but abundant hematite only exists within the clasts. Hysteresis parameters show the matrix has more multi-domain and likely larger magnetic grains than the clasts.
    Magnetic directions are different in the clasts and matrix supporting a two-phase oil-staining event. Moreover, paleomagnetic directions for the clasts after tilt correction (82.6°N and 155.2°E) are consistent with biodegradation processes in the Early Cretaceous. Consistent directions in separate clasts imply the biodegradation and magnetite formation took place following transportation and incorporation of the oil-cemented clasts into the conglomerate bed. Magnetic directions reveal that the Mupe Bay matrix has a remanent magnetization corresponding to today's magnetic field, confirming the matrix represents an active oil seep.
    This study represents an unprecedented use of magnetic data to date the onset of oil migration in a basin. The classic two-stage oil-staining scenario, which constrains the onset in the Wessex Basin to the Early Cretaceous, is supported by our data.

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    Englefield , Sir H.C. 1816. A Description of the Principal Picturesque Beauties, etc., of the Isle of Wight. With additional observations on the strata of the Island, and their continuation in the adjacent parts of Dorsetshire, by T. Webster. Payne and Foss, London. [Classic early work]

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    Paul Ensom is the notable and well-known author of very many papers and notes regarding the Purbeck Group of Dorset (and other Dorset topics, including Lias, Middle Jurassic and Kimmeridge Clay). For several years the geological editor of the Proceedings of the Dorset Natural History and Archaeological Society.

    Ensom P.C. 1980. The geological displays in the Dorset County Museum, Dorchester. Geological Section, Hampshire Field Club and Archaeological Society Newsletter, No. 2.

    Ensom, P.C. 1982. Dinosaur footprints at 19 Townsend Road, Swanage. Proceedings of the Dorset Natural History and Archaeological Society, vol. 103, p. 141. By Paul Ensom.

    Ensom, P.C. 1982. Ichnites sp. from Worbarrow Tout, near West Lulworth. Proceedings of the Dorset Natural History and Archaeological Society, vol. 103, p. 141.

    Ensom, P.C. 1982. Type, figured and cited specimens in the geological collections of the Dorset County Museum. Geological Curator, vol. 3, No. 4, p. 237.

    Ensom, P.C. 1983. Ichnites sp. from the Chief Beef Beds and Broken Shell Limestone, Durlston Beds, Purbeck Limestone Formation, Durlston Bay, Swanage. Proceedings of the Dorset Natural History and Archaeological Society, vol. 104, p. 201.

    Ensom, P.C. 1983. Footprints from the Lower Cretaceous of southern England. Geological Curator, vol. 3, No. 8, p. 487.

    Ensom, P.C. 1983. Correction to: 'Multiple trackways from the Isle of Purbeck', J.B. Delair. In Proceedings of the Dorset Natural History and Archaeological Society, 102, 1982. Proceedings of the Dorset Natural History and Archaeological Society, vol. 104, pp. 201-202.

    Ensom, P.C. 1984. Ichnites spp. in Durlston Bay and on Worbarrow Tout. Proceedings of the Dorset Natural History and Archaeological Society, vol. 105, pp. 166-167.

    Ensom, P.C. 1984. Purbeckopus pentadactylus Delair . Proceedings of the Dorset Natural History and Archaeological Society, vol. 105, pp. 166.

    Ensom, P.C. 1984. A temporary exposure in the Purbeck Limestone Formation (Upper Purbeck Beds) at Friar Waddon Pumping Station, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 105, pp. 89-91.

    Ensom, P.C. 1984. Vertical packing of oyster shells in the Cinder Bed of Worbarrow Tout. Proceedings of Dorset Natural History and Archaeological Society, vol. 105, pp. 167-168.

    Ensom, P.C. 1984. A syn-sedimentary slump and folds in the Purbeck Limestone Formation at Worbarrow Tout. Proceedings of Dorset Natural History and Archaeological Society, vol. 105, p. 168.

    Ensom, P.C. l985. An annotated section of the Purbeck Limestone Formation at Worbarrow Tout, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 106, pp. 87-91. [Useful log compatible with that of Clements for Durlston Bay]

    Ensom, P.C. l985. A correction and additions to the distribution of Ichnitesin the Purbeck Limestone Formation of Worbarrow Tout and Durlston Bay. Proceedings of Dorset Natural History and Archaeological Society, vol. 106, pp. 166-167.

    Ensom, P.C. 1985. Tectonic fissures in the Marly Freshwater Member, Purbeck Limestone Formation, Worbarrow Tout, Dorset. Proceedings of Dorset Natural History and Archaeological Society, 106, pp. 165-166.
    Ensom, P.C. 1985. Derived fossils in the Purbeck Limestone Formation, Worbarrow Tout, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 106, p. 166.

    Ensom, P.C. 1985. A correction and additions to the distribution of Ichnites spp. in the Purbeck Limestone Formation of Worbarrow Tout and Durlston Bay, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 106, pp. 166-167.

    Ensom, P.C. 1985. Pyriporopsis portlandensis Pohowsky 1973, a bryozoan from the Scallop Member, Purbeck Limestone Formation, of Worbarrow Tout, Dorset.Proceedings of Dorset Natural History and Archaeological Society, vol. 106, p. 167.

    Ensom, P.C. 1985. New bivalve records from the Purbeck Limestone Formation, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 106, p. 167.

    Ensom, P.C. 1985. A barnacle from the Cinder Member, Purbeck Limestone Formation, Worbarrow Tout, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 106, pp. 167-168.

    Ensom, P.C. 1986. Ichnites sp. from the Upper Cypris Clays and Shales Member (Purbeck Limestone Formation) near Harman's Cross, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 107, p. 183.

    Ensom, P.C. 1986. Purbeckopus pentadactylus Delair; a figured specimen re-discovered. Proceedings of Dorset Natural History and Archaeological Society, vol. 107, p.183.

    Ensom, P.C. 1986. Palaeontological Association field trip to Dorset, September 1985. Proceedings of Dorset Natural History and Archaeological Society, vol. 107, p. 184.

    Ensom, P.C. 1986. Association field meeting on the Jurassic of Dorset, 27-29 September 1985. Palaeontological Association Circular, London, p. 123.

    Ensom, P.C. 1987. Notes on Ichnites spp. in the Purbeck Limestone Formation, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 108, p. 206.

    Ensom, P.C. 1987. A remarkable new vertebrate site in the Purbeck Limestone Formation on the Isle of Purbeck. Proceedings of Dorset Natural History and Archaeological Society, vol. 108, pp. 205-206. [See also Correction to .. A remarkable new vertebrate site ...; in Proceeding of Dorset Natural History and Archaeological Society for 1989, published 1990, p. 133. Correlation with bed WB112 should have read WB117.]

    Ensom, P.C., 1987, [Dinosaur tracks in Dorset. Anon, but based almost verbatim on text supplied by PCE]. Geology Today, 3, pp. 182-183.

    Ensom, P.C. 1987. Notes on Ichnites spp. in the Purbeck Limestone Formation, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 108, p. 206.

    Ensom, P.C. 1988. Excavations at Sunnydown Farm, Langton Matravers, Dorset: Amphibians discovered in the Purbeck Limestone Formation. Proceedings of Dorset Natural History Archaeological Society, 109, 148-150. [Sauropod footprints, salamanders, multituberculate mammals. Iguanodon footprints. Cherty Freshwater Member. Also see paper in Palaeontology giving full description of mammals.]

    Ensom, P.C. 1989, Sunnydown Farm sauropod footprint site. Proceedings of the Dorset Natural History and Archaeological Society, vol. 110, pp. 167-8.

    Ensom, P.C. 1990, Correction to 'A remarkable vertebrate site in the Purbeck Limestone Formation on the Isle of Purbeck', P. C. Ensom, Proceedings of the Dorset Natural History and Archaeological Society, 108, pp. 205-206. Proceedings of the Dorset Natural History and Archaeological Society, vol. 111, p. 133.

    Ensom, P.C. 1993. A provisional list of the fauna and flora of the upper microvertebrate horizon, Cherty Freshwater Member, Purbeck Limestone Formation, Isle of Purbeck, Dorset. The Morrison Times, No 2, pp. 10-12.

    Ensom, P.C. 1994. An unusual tool-mark in the Purbeck Limestone Formation, Durlston Bay, Dorset. Proceedings of the Dorset Natural History and Archaeological Society, vol. 115, p. 185.

    Ensom, P.C. 1994. A new vertebrate trackway from the Intermarine Member, Purbeck Limestone Formation, Dorset. Proceedings of Dorset Natural History and Archaeological Society, 115, 183-184.

    Ensom, P.C. 1997. Reptile eggshell from the Purbeck Limestone Group of Dorset, southern England. Proceedings of Dorset Natural History and Archaeological Society, for 1996, vol. 118, pp. 79-83.

    Ensom, P.C. 1997, The repair of microvertebrate mammal teeth using surface tension and capillary action, The Geological Curator, vol. 6 (8), pp. 293-295.

    Ensom, P.C. 1999, Reptile eggshell and the remains of embryonic(?) dinosaurs from the Purbeck Limestone Group (Upper Jurassic-Lower Cretaceous) of Dorset. Abstracts: Life and Environments in Purbeck Times, 19th - 22nd March 1999, pp.18-19.

    Ensom, P.C., 1999, Vertebrate trace fossils from the Purbeck Limestone Group of southern England. In: Milner, A. [Editor]. Abstracts: Life and Environments in Purbeck Times, 19th - 22nd March 1999: pp. 20-21.

    Ensom, P.C., 2002, Reptile eggshell, tiny vertebrate remains and globular calcified cartilage from the Purbeck Limestone Group of southern England. pp.221-239. In: Milner, A. R. and Batten, D. J. (eds), Life and Environments in Purbeck Times, Special Papers in Palaeontology, 68, 268 pp.

    Ensom, P.C. 2002. Vertebrate trace fossils in the Purbeck Limestone Group of Southern England. Pp. 203-220 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268 pp.
    Abstract: The Purbeck Limestone Group (late Jurassic-early Cretaceous) contains a rich vertebrate trace fossil fauna. Research on this fauna has been almost entirely concerned with dinosaur tracks. By contrast, the feeding traces and coprolites, which are occasionally abundant, have received little attention. The implications of some recent papers, including those where ichnotaxa are assigned, are considered along with the stratigraphic and geographic distribution of reptilian tracks. A plan of the principal footprint horizon at Townsend Road, Swanage, is presented and the more unusual aspects of the site illustrated. An appendix gives a comprehensive listing of published and manuscript accounts dealing with footprints from these strata. Some of the neglected feeding traces and coprolites are described and illustrated for the first time.

    Ensom, P. 2002. The Purbeck Limestone Group of Dorset, southern England: a guide to lithostratigraphic terms. Pp; 7-11 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268 pp. Report from a symposium on the Purbeck Group at the Dorset County Museum, Dorchester, Dorset, March 19-22, 1999. By Paul Ensom.

    Ensom, P.C. 2009. Conchostracans in the Intermarine Member, Durlston Formation, Purbeck Limestone Group, of Dorset, southern England. Proceedings of the Dorset Natural History and Archaeological Society, vol. 130, pp. 234-236. By Paul Ensom.
    Abstract: The discovery in 2008 of conchostracans Liograpta subquadrata (J. de C. Sowerby) in the Intermarine Member, extends the known range of these extant arthropods from the Lulworth Formation into the Durlston Formation of the Purbeck Limestone Group of Dorset, southern England.

    Ensom, P.C. 2009. A dinosaur track from the Wealden Group (Lower Cretaceous), Worbarrow Bay, Dorset, southern England. Proceedings of the Dorset Natural History and Archaeological Society, Natural History Reports, pp. 233-234. By Paul Ensom.

    "While leading a field trip for the Open University Geological Society (South West Branch) in October 2008, the cast of a single, indifferently preserved, apparently tridactyl track was found on a fallen and partially buried block of fine-grained, pale sandstone at the foot of a cliff at Worbarrow Bay (NGR SY 86949 80313). In addition a second track is hinted at with a single putative digit preserved on one edge. .... The conclusion reached was that Stewart's Bed no. 7 was probably the source, the in situ bed exhibiting some structures similar to the fallen block. ..."

    Ensom, P. 2010. The Purbeck Limestone Group (Tithonian-Berriasian) Succession Between Bacon Hole and Mupe Bay, near West Lulworth, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 131, pp. 140-144. By Paul Ensom, who has published many papers on the Purbeck Group and has logged the Worbarrow Tout, Purbeck section.

    Example part of the three-page lithostratigraphic log for the Purbeck Group of Bacon Hole and Mupe Bay, Dorset, by Ensom (2010)

    [This includes a very useful graphic log of 157 beds at Bacon Hole, shown in 3 pages.]
    This log is Appendix 2 in: Ensom, P. 2010. Lithostratigraphic sections through the Purbeck Limestone Group (Tithonian-Berriasian) at five Regionally Important Geological/Geomorphological Sites (RIGS) on the Isle of Purbeck, and at Bacon Hole near West Lulworth, Dorset, southern England. Proceedings of the Dorset Natural History and Archaeological Society, vol. 131, 2010, pp. 127-144.


    Ensom, P. 2010. Lithostratigraphic sections through the Purbeck Limestone Group (Tithonian-Berriasian) at five Regionally Important Geological/Geomorphological Sites (RIGS) on the Isle of Purbeck, and at Bacon Hole near West Lulworth, Dorset, southern England. Proceedings of the Dorset Natural History and Archaeological Society, vol. 131, 2010, pp. 127-144. By Paul Ensom.
    The creation of a virtual field trip principally featuring the Purbeck Limestone Group on the Isle of Purbeck, Dorset, southern England by Dorset's Important Geological/Geomorphological Sites Group, led to the production of logs of the strata exposed in the five Regionally Important Geological/Geomorphological Sites. The logged sections of these are published along with one for the Purbeck Limestone Group exposed between Bacon Hole and the southern margin of Mupe Bay near West Lulworth. Insects recovered from one of the sites are listed. Reference is made to the distribution of silicified wood based on observation in the field. The presence of microinvertebrates, dinosaur tracks, and of reddened strata at certain horizons is recorded

    Ensom, P.C., Clements, R.G., Feist-Burkhardt, S., Milner, A.R., Chitolie, J., Jeffrey, P.A. and Jones, C. 2009. The age and identity of an ichthyosaur reputedly from the Purbeck Limestone Group, Lower Cretaceous, Dorset, southern England. Cretaceous Research, vol. 30, Issue 3, June 2009, pp. 699-709.
    Ichthyosaurs are widespread in Mesozoic marine sequences. The marginal marine to terrestrial strata of the Cretaceous Purbeck Limestone Group of Dorset are an unlikely source for the remains of such animals. A specimen in the collections of the Oxford University Museum of Natural History, acquired in the nineteenth century, is recorded as collected from these strata. Despite the suggestion that this specimen might represent a relict taxon of a much earlier lineage in the evolution of ichthyosaurs [Delair, J.B., 1969. The first record of the occurrence of ichthyosaurs in the Purbeck. Proceedings of the Dorset Natural History and Archaeological Society, 90, 128-132], its age and source have not been questioned. A comprehensive investigation of the matrix, including a palynological study, confirms a Purbeck Limestone Group origin for the specimen. Reassessment of the preserved postcranial skeleton provides evidence that the specimen, though strictly indeterminate, is consistent with attribution to a juvenile of an ophthalmosaurid such as Brachypterygius. The 'notched' phalanx previously considered to be 'primitive' is an artefact of damage to the specimen, either as the slab broke away from the cliff or shore, or during collection and subsequent preparation.
    Extract from the Conclusions:
    "The petrology and the invertebrate fauna are compatible with a source from the Scallop Member (DB 148-153) and the lowest bed of the Corbula Member (DB 154) of the Purbeck Limestone Group of Durlston Bay, Swanage, Dorset (Clements, 1993). This is supported by the palynology which places the specimen somewhere between the Cherty Freshwater Member and the top of the Upper 'Cypris' Clays and Shales Member.
    There is no evidence that the indeterminate Purbeck ichthyosaur represents a distinct lineage separate from other Late Jurassic taxa as suggested by Delair (1969) but in its only taxonomically useful feature, is consistent with what might be expected in a juvenile ophthalmosaurid. We leave open to future investigation the question as to why this ichthyosaur's remains came to be found within an essentially non-marine group of rocks, although we have sympathy with the view that it may simply have been living there.

    Ensom, P.C. and Delair, J.B. 2007 [2008]. Dinosaur tracks from the Lower Purbeck strata of Portland, Dorset, southern England. Geoscience in Southern England [Proceedings of the Ussher Society], vol. 11, 309-325..
    Dinosaur tracks from strata below the Cherty Freshwater Member, Lulworth Formation, Purbeck Limestone Group, of Dorset had not been recorded formally until 2002 when Professor Michael House published a preliminary note, in the Proceedings of the Dorset Natural History and Archaeological Society. He flagged the 2001 discovery of a number of blocks of the 'Thick Slatt', Hard Cockle Member, with casts of dinosaur tracks preserved on their lower surfaces, in a quarry on the Isle of Portland. New light is shed on the source of the tracks, and the history of their discovery is documented. The methods employed to record them are described. The traces are placed in their stratigraphic and palaeoenvironmental settings.
    In this paper, how the tracks were made is described, and most importantly it is concluded that they are preserved as transmitted casts. Three distinct types of tridactyl track attributable to bipedal dinosaurs are recognized, as well as isolated tracks which are interpreted as belonging to quadrupedal dinosaurs. Evidence is presented to support the interpretation that one of the tracks assigned to a quadrupedal dinosaur was produced by a sauropod. Despite their apparent differences, it is suggested that the majority of the tridactyl tracks were left by one species of dinosaur which was almost certainly herbivorous and lived in groups. One trackway may have been made by a carnivorous dinosaur.

    Ensom, P.C., Evans, S.E., Francis, J.E., Kielan-Jaworowska, Z. and Milner, A.R. 1994. The fauna and flora of the Sunnydown Farm Footprint site and associated sites: Purbeck Limestone Formation, Dorset. Proceedings of the Dorset Natural History and Archaeological Society, vol. 115, 181-182.

    Ensom, P.C., Evans, S.E. and Milner, A.R. 1991. Amphibians and reptiles from the Purbeck Limestone Formation (Upper Jurassic) of Dorset. Fifth Symposium on Mesozoic Terrestrial Ecosystems and Biota. Extended Abstracts - edited by Zofia Kielan-Jaworowska, Natascha Heintz and Hans Arne Nakrem. Contributions from the Paleontological Museum, University of Oslo, No. 364, 1991. Pp 19-20. [Enimatic lizard Durotrigia.]

    Ensom, P., Kenrick, P., Edmonds, R., Cripps, J. and Hayes, P. 2009. A fossil tree trunk in the Intermarine Member, Durlston Formation, Purbeck Limestone Group of Dorset, southern England. Proceedings of the Dorset Natural History and Archaeological Society, vol. 130, 2009, 183-187.
    A new and unusual pipe-like feature, that we interpret as a partially exposed fossil tree trunk, has been exposed in the cliffs of Durlston Bay, Swanage. To the best of our knowledge fossil trees have not been recorded from the Durlston Formation of the Purbeck Limestone Group of Dorset.

    Ensom, P.C. and Sigogneau-Russell, D. 1998. New dryolestoid mammals from the basal Cretaceous Purbeck Limestone Group of southern England. Paleontology , 41, 35-55. Abstract: The dryolestoid mammal Dorsetodon haysomi gen. et sp. nov. is described from the Purbeck Limestone Group (Lower Cretaceous) of southern England, on the basis of lower molars. Dorsetodon is assigned to the Paurodontidae, a family of Theria previously known only from North America. The distinction between Paurodontidae and Henkelotheriidae (from the Upper Jurassic of Portugal), although maintained for lack of solid contrary data, is argued to have been based on variable or subjective characters. A further small mammal, Chunnelodon alopekodes gen, et sp. nov., representing an undetermined cladotherian family, is also described from lower molar teeth. The non-procumbent paraconid on the lower molar places Chunnelodon as a sister-taxon to the Laurasian Dryolestoidea.

    Ensom, P. and Sigogneau-Russell, D. 2000. New symmetrodonts (Mammalia, Theria) from the Purbeck Limestone Group, Lower Cretaceous, southern England. Cretaceous Research, 21, 767-779. Abstract: The genus Spalacotherium Owen was initially created from material collected in the Purbeck Group in 1854. A new species, S. evansae, is here described from a Purbeck site discovered in 1986; it is represented not only by lower and upper molars, but possibly also by milk molars. The genus Tinodon was, until now, known only from the slightly older Morrison Formation in Wyoming, USA; a few lower molars and an upper molar also from the site are attributed to a new and smaller species, T. micron, which adds one more genus that is common to the two formations. The attributed upper molar of T. micron is especially interesting in that it yields new data on a taxon widely discussed in symmetrodont phylogeny, while at the same time raising problems of cusp homology.

    Ensom, P. and Turnbull, M. 2011. Geology of the Jurassic Coast; The Isle of Purbeck; Weymouth to Studland.. By Paul Ensom and Malcolm Turnbull. Jurassic Coast Trust. Coastal Publishing, Wareham. 128pp. Price 9 pounds, 95 pence. This is a very well-illustrated guide with many good colour photographs that are labelled in terms of stratal units. The text is in easily-readable, non-specialist language. There is a glossary for non-geologists. Some further reading is given in a list at the back. -------------------------------------------------------------------------------------------

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    Escapa , I., Cuneo and Axsmith, B. 2008. A new genus of the Cupressaceae (sensu lato) from the Jurassic of Patagonia: Implications for conifer megasporangiate cone homologies. Review of Palaeobotany and Palynology, 151, Issues 3-4, Sept. 2008, pp. 110-122. By Ignacio Escapa, Ruben Cuneo, and Brian Axsmith. Available online 20 March 2008. [This paper is not on the Purbeck Group, but may be relevant to the study of Purbeck fossil trees].
    Abstract: A new conifer, Austrohamia minuta, gen. et sp. nov., from the Jurassic of Chubut province, Argentina, is described and proposed as the type species of a new genus of the Cupressaceae s.l. The material consists of impressions represented by well-preserved leafy twigs and branches as well as ovulate and pollen cones. The ovulate cones show a simple organization with helically arranged bracts, each bearing one or two inverted ovules on their adaxial surfaces. Pollen cones occur in terminal clusters subtended by modified leaves. This conifer possesses a combination of characters indicating placement within the basal Cupressaceae (i.e. the former "Taxodiaceae"). This conclusion is supported by a phylogenetic analysis that places the Argentinean fossil close to the extant genera Athrotaxis and Cunninghamia, and the fossil genera Elatides and Sewardiodendron. In this context some classical characters in conifer systematics are reconsidered in order to clarify their homologies and significance in the early evolution of the Cupressaceae. This represents the first convincing record of the Cupressaceae s.l. in Jurassic floras from the southern hemisphere.
    Evans, S.E. 1994. A new Anguimorph lizard from the Jurassic and Cretaceous of England. Palaeontology, vol. 37, part 1, 1994, pp. 33-49. By Susan E. Evans. [bones from the Purbeck Group].

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    Falconer , H. 1857. Description of two species of the fossil mammalian genus Plagiaulax from Purbeck. Quarterly Journal of the Geological Society, London, 13, 261-282.

    Falconer, H. 1862. On the disputed affinity of the mammalian genus Plagiaulax .Quarterly Journal of the Geological Society, 18, 348-369.
    Feist , M., Lake, R.D. and Wood, C.J. 1995. Charophyte biostratigraphy of the Purbeck and Wealden of southern England. Palaeontology, 38, Part 2, 407-442.
    Abstract: The distribution of charophyte assemblages in the Purbeck and Wealden sequence of southern England has been established from borehole samples from the Weald and from outcrop material collected in Dorset, Wiltshire and the Isle of Wight. Of the twenty-one taxa represented, three are new: Globator rectispirale, Clypeator britannicus and Sphaerochara andersonii; three new combinations are proposed: Globator praecursor, Globator protoincrassatus and Atopochara triquetra. The Chinese Valanginian species Flabellochara xiangyunensis is recognised for the first time in Europe. In the context of the phylogeny of the Family Clavatoraceae, G. rectispirale represents the Jurassic ancestor of the Globatorlineage and a separate origin is suggested for both Flabellochara and Clypeator. The correlation established with the Tethyan realm locate the Jurassic Cretaceous boundary within the Lulworth Formation of the Purbeck Group; in this context, the whole 'Purbeck' sequence of Swindon (Wiltshire) is attributed to the Upper Tithonian. The distribution of the Clavatoraceae indirectly confirms the contemporaneity of the Boreal Galbanites kerberus and Titanites anguiformis with the Tethyan 'Durangites' ammonite zones. For the Wealden Supergroup, the charophyte data affirm the Hauterivian-Barremian boundary near the upper division of the Weald Clay and the Upper Barremian is identified at the base of the Vectis Formation of the Isle of Wight.

    Feist, M. and Schudack, M. 1991. Correlation of charophyte assemblages from the non-marine Jurassic-Cretaceous transition of NW Germany. Cretaceous Research, vol. 12, pp. 495-510.

    The Rev. Osmond Fisher writes in 1854 about his work on the Purbeck strata of Dorsetshire

    Fisher , O. 1856. On the Purbeck strata of Dorsetshire. Transactions of the Cambridge Philosophic Society, 9, 555-581. [Classic early log of the Durlston section with useful faunal information. See Wilding, 1988 for biography of the Rev. Osmond Fisher]
    Fitton , W.H. 1835. Notice on the junction of the Portland and Purbeck strata on the coast of Dorsetshire. Proceedings of the Geological Society, 2, 185-187.

    Fitton, W.H. 1836. Observations on some of the strata between the Chalk and the Oxford Oolites, in the south-east of England. Transactions of the Geological Society, London, 4, 103-389.
    Folk , R.L. Spectral subdivision of limestone types. In: Classification of Carbonate Rocks (Ed. by L.C. Pray and R.C. Murray), pp. 62-84. Memoir of the American Association of Petroleum Geologists, No. 1. [This is relevant to naming of limestone rock types seen in the Purbeck Group.]

    Folk, R. L. and Pittman, J. S., 1971, Length-slow chalcedony: a new testament for vanished evaporites: Journal of Sedimentary Petrology, vol. 41, pp. 1045-1058. [Relevant to Purbeck evaporites.]
    Forbes , E. 1851. On the succession of strata and distribution of organic remains in the Dorsetshire Purbecks. Reports of the British Association for the Advancement of Science (1850), Abstracts, pp. 79-81.
    Francis, J. Papers by Professor Jane Francis, the Purbeck tree and soil specialist. (She completed her Ph.D. thesis on the Purbeck Group at Southampton University and supervised by IMW).

    Francis , J. E. 1983. The Fossil Forests of the Basal Purbeck Group (Upper Jurassic) of Dorset, Southern England. Unpublished Ph.D. Thesis, University of Southampton.

    Francis, J. E. 1986 The Calcareous Paleosols of the Basal Purbeck Group (Upper Jurassic) Southern England. p. 112-138 in: V.P. Wright, (Ed.) Paleosols: Their recognition and interpretation. Blackwell, Oxford. (Basal Purbeck Dirt Beds of Lulworth and Portland)

    Francis, J.E. 1983. The Dominant Conifer of the Jurassic Purbeck Group, England. Palaeontology, 26, 277-294.
    Fossil trees are preserved in situ in fossil soils in the Lower Purbeck (Upper Jurassic) strata of Dorset. Silicified tree trunks, still rooted in the soils, stand erect and protrude into the overlying limestones. Numerous trunks and branches lie on the soils, which also contain conifer shoots. The forests were dominated by one kind of conifer with wood, named here as Protocupressinoxylon purbeckensis sp. nov., foliage belonging to the species Cupressinocladus valdensis (Seward) and with male cones yielding Classopolis pollen. A reconstruction of the anatomy and habit of the tree is given. The Lower Purbeck [Lulworth Formation] palaeoclimate is discussed using the evidence of tree growth rings and the character of the associated sediments.
    [ Key paper. Protocupressinoxylon purbeckensis a cypress or juniper-like tree. Cycadophytes also occurred but were much less common. Incidently, the male cone was found in the Great Dirt Bed, marginal facies at Godnor Quarry. See also other papers on Purbeck cones etc., incuding Barker et al. 1975 and Steart et al. 2014.]


    Francis, J. 1996. Paddling in the Portlandian: a new record of dinosaur footprints from the Purbeck/Portland transition, Portland. Palaeontological Association Newsletterr, No. 32. Abstracts for the 1996 Annual Meeting. One paragraph only (as below) on page xv of the Abstracts volume. "A new set of dinosaur footprints has been discovered on the Isle of Portland on an exposed bedding surface in a disused quarry. The footprints are shallow impressions of small (up to 14 cm in length broad three-toed prints, very similar to those made by bipedal tridactly ornithopods such as Iguanodon . They do not appear to form a distinct trackway, more of a meandering stroll assemblage. The footprints occur in the upper surface of a transitional bed between the underlying marine shelly oolites of the Portland Stone Formation and overlying palaeosols and algal limestones of the Purbeck Lulworth Formation. This bed represents a change from high energy carbonate shelf facies to shallower, lower energy conditions prior to the onset of terrestrial soils/hypersaline lagoon environments. This is the lowest stratigraphical occurrence of footprints known in the Purbeck Group, since previously recorded footprints occur much higher in the Middle Purbeck Durlston Formation. These footprints show that ornithopod dinosaurs paddled happily in the shallows of the Portlandian seas in the Mediterranean climate that prevailed at that time." End of Abstract. By Jane Francis, Department of Earth Sciences, University of Leeds, Leeds, LS2 9JT. [The location is believed to be a small abandoned quarry of Portland Stone with basal Purbeck Caps and Dirt Beds above Freshwater Bay, on the east cliffs of Portland, map reference 691702, but nothing is very obvious there at present. The bed is the Transition Bed, a thin and laminated pelletoidal limestone, characterised in many places by a fauna of small lagoonal gastropods, such as Hydrobia as moulds and with some foraminifera visible in thin-section. It is fused directly to the top of the Portland Freestone which is characterised by the shells of large marine molluscs. IMW]

    Francis, J.E., and Harland, B.M. 2006. Termite borings in Early Cretaceous fossil wood, Isle of Wight, UK. Cretaceous Research, 27, Issue 6, December 2006, 773-777.
    Abstract: A pellet-filled boring in fossil wood is described from the Early Cretaceous Wessex Formation (Barremian), Isle of Wight. The cylindrical boring, approximately 1 cm in diameter, is filled with carbonaceous pellets with a hexagonal shape, preserved within a matrix of pyrite. Features of the boring suggest that it was made by termites that bored into the wood, either when the tree was alive or in the early stages of decay on the forest floor. This evidence of termite activity complements previous records of termite wing fossils and faecal pellets in Wealden sediments and is evidence for social behaviour in Wealden insects. This is one of the oldest records of termite borings in wood.

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    Fursich , F.T., Palmer, T.J. and Goodyear, K.L. 1994. Growth and distintegration of bivalve-dominated patch reefs in the Upper Jurassic of southern England. Palaeontology, vol. 37, Part 1, pp 131-171. By Franz T. Fursich, Timothy J. Palmer and Kay L. Goodyear.
    Abstract: Patch reefs, up to 4 metres high and 8 metres across, grew amongst oolith shoals at the top of the Portland Limestone Formation (Portlandian, Upper Jurassic) on the Isle of Portland, southern England. Principal reef framebuilders, which provided between 55 and 70 per cent of the reef volume, were cementing bivalves, solenoporacean algae, and bryozoans. The remaining pore-space in the reef was filled by sediment, most of which is in the form of a precipitated peloidal cement. The cement lithified the reef while it was still exposed on the sea floor, and was probably precipitated under bacterial control. A diverse accessory fauna of small cementing encrusters and nestlers includes groups such as terebratulid brachiopods and lithistid sponges -that have not previously been found in the Portland Limestone. Serpula (Cycloserpula) striatissima sp. novo and Carterochaena pulcherrima gen. et sp. novo are described. Both the primary organic framework of the reef and the submarine cements were bored by a variety of endoliths, which locally removed as much as 40 per cent of the reef volume. Vacated borings acted as sites for precipitation of further peloidal cement. Borings are well preserved as natural three-dimensional casts in cases where they originally perforated an aragonite substrate which has since dissolved. New taxa of borings consist of Cunctichnus probans ichnogen. et ichnosp. nov., Spirichnus spiralis ichnogen. et ichnosp. nov., Talpina bromleyi ichnosp. nov., and Entobia cervicornis ichnosp. novo.
    [This is a very interesting paper on Portland Stone sedimentology, in addition to palaeoecology, and is also relevant to Purbeck Group sedimentology.]

    [Example extract, p. 136:
    "Later Diagenenesis:
    All facies of the Portland Roach are characterised by complete leaching of aragonite, so that all aragonite taxa are preserved as internal and external moulds (Pl.2, fig. 1). The dissolution probably occurred very soon after completion of sedimentation when the sequence was uplifted into the meteoric realm. The overlying basal Purbeck rocks contain soils and freshwater ostracodes (Arkell 1947; Townson 1975; R.C. Whatley pers. comm.) so downward flow of meteoric water through at least the upper part of the Portlandian sediments must have occurred, and would probably have been rapid at some times of the year, given the marked seasonality of Lower Purbeck times (Francis, 1984). In contrast to the fate of aragonite, low-magnesian calcite shells of bryozoans, brachiopods, some molluscs, and the winter layers (cf. Wright 1985) of the rhodophyte Solenopora are preserved with full microstructural detail, and show only minor silicification (presumably the result of remobilisation of silica from sponge spicules: Townson 1975). However a third style of preservation is evident in serpulids, encrusting forams (Nubeculina) and in the darker summer layers of Solenopora. In these taxa preservation is varible, ranging from good (with little or no apparent structural alteration) to mouldic (with complete loss of original shell; Pl.1, fig. 2). In between (particularly in Solenopora) lie examples of partial replacement by diagenetic calcite with varying amounts of loss of detail of the original microfabric." [continues]

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    Gore, C.H., Chatwin, C.P. and Pringle, J. 1922. Excursion to Swindon. Proceedings of the Geologists' Association, vol. 33.
    Gavshyn , V.M. and Zakharov, V. A. 1996. Geochemistry of the Upper Jurassic - Lower Cretaceous Bazhenov Formation, West Siberia. Economic Geology, 91, 122-133.
    Gillet , A. and Russel, B.K. 1991. Around Heathfield in Old Photographs; a Second Selection. By Alan Gillet and Barry K. Russell. Alan Sutton Publishing Ltd, 160 pp. ISBN 0-86299-950-2. Paperback, price 7 pounds, 95p. A few photographs are included which show the site of the discovery of natural gas, methane, in the Purbeck Group of the Weald at and near Heathfield railway station, Sussex, UK. Information from the captions of the photographs is given below:
    p. 21. Photograph of hotel and a shed-like building with a ladder. Caption: "Natural gas was accidentally discovered in Heathfield when drilling for water in the stable yard of the newly built Station Hotel in 1895. When it was also discovered only months later near the rail tunnel entrance, a company, the Natural Gas Fields of England Ltd, was set up to exploit the find (encouraged by Uckfield solicitor Charles Dawson of Piltdown Man notoriety). One of several local boreholes was drilled on the wasteland at the rear of the original Temperance Hotel."
    p. 23. Photograph of a railway station employee, perhaps the station master, standing dangerously close (just a few metres) from a large flare of burning gas about 10 metres high. The flare is emerging from a borehole pipe projecting about 1.5 m. above the railway level.
    "While drilling for a water supply near the mouth of the 266-yd tunnel at Heathfield station in August 1896, a strong smell of gas was noticed. On lighting a match, a name shot sixteen feet into the air. This was only extinguished with great difficulty - by throwing wet cloths over the bore-tube. A cast-iron cap and stop-cock was later screwed on and, by 1898, gas from this bore-hole was used to light Heathfield station."
    p. 23 (lower photograph). The setting of the gas borehole is shown in this photograph. It is in a railway cutting adjacent to a water tank and a signal and a brick bridge. On the far side of the bridge is the railway station. Another photograph shows a gas container at the coal yard.
    Caption: "The view from the mouth of the tunnel, looking towards the road bridge. Beyond the large water tower (needed in an age of steam trains) are two gasholders which would expand upwards as they were filled with natural gas from the nearby bore-hole. A man appears to be working at the bore-hole pipe while compressed gas cylinders can be seen lying on the ground to his left. The cylinders were filled with natural gas and sent off for laboratory testing on mine safety etc."


    Gradstein, F.M., Ogg, J.G., Schmitz, M.D. and Ogg, G. 2012. The Geologic Time Scale 2012. Elsevier. In a two volume paperback set. Price £52.49p. from Amazon.UK in 2013 (also available as a Kindle Edition). By Felix M. Gradstein, James G. Ogg, Mark D. Schmitz and Gabi M. Ogg. This is an update of Gradstein, F., Ogg, J. and Smith, A. 2004. A Geologic Time Scale, 2004. Cambridge. (one volume, 585pp.).
    The Geologic Time Scale 2012, winner of a 2012 Prose Award Honorable Mention for Best Multi-volume Reference in Science from the Association of American Publishers, is the framework for deciphering the history of our planet Earth. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This 2012 geologic time scale is an enhanced, improved and expanded version of the GTS2004, including chapters on planetary scales, the Cryogenian-Ediacaran periods/systems, a prehistory scale of human development, a survey of sequence stratigraphy, and an extensive compilation of stable-isotope chemostratigraphy. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable wall chart of the complete time scale for use as a handy reference in the office, laboratory or field. This is the most detailed international geologic time scale available that contextualizes information in one single reference for quick desktop access. It gives insights in the construction, strengths, and limitations of the geological time scale that greatly enhances its function and its utility. I

    Gray , W. 1861. On the geology of the Isle of Portland. Proceedings of the Geologists' Association, 1, 128-147.
    Grekoff , N. 1953. Sur l'utilisation des microfaunes d'ostracodes dans la stratigraphique precise du passage Jurassique-Cretace (facies continentaux). Extrait de la Revue de l'Institut Franc du Petrole et Annales des Combustibles Liquides, p. 362-?
    Grey , K., Moore, L.S., Burne, R.V., Pierson, B.K. and Bauld, J. 1990. Lake Thetis, Western Australia: and example of saline lake sedimentation dominated by benthic microbial processes. Australian Journal of Marine and Freshwater Research, 41 (2), 275-300.
    Lake Thetis is a saline coastal lake in south-western Australia, a region of winter rainfall and summer drought. The lake demonstrates the close relationships between environmental variation and the nature of resident benthic microbial communities. Crenulate cyanobacterial mats occur in the low-lying areas adjacent to the lake. Lithified stromatolites with patches of living coccoid cyanobacterial mat characterize the littoral area, whereas a thick flocculent mat composed of phototrophic prokaryotes (principally purple sulfur bacteria) and diatoms has accumulated in the central lake basin. Lake Thetis is distinguished from other coastal saline lakes by the presence of the unusual flocculent mat and by the juxtaposition of this microbial community to the marginal lithified stromatolites. Further, some of the latter exhibit internal digitate columnar branching which, though common in Precambrian examples, is rare in modern environments. [compare to Purbeck cyclindrical stromatolites at the Fossil Forest and on the Isle of Portland. see: Fossil Forest webpage. I am very grateful to Alan Holiday for drawing attention to the Lake Thetis analogue.]
    Griffith, J. and Patterson, C. 1963. The structure and relationships of the Jurassic fish Ichthyokentema purbeckensis. Bulletin of the British Museum (Natural History), Geology, vol. 8, No. 1., London, 43 pp. and 4 plates.
    Synopsis: Ichthyokentema purbeckensis (Davies), a halecostome from beds of marine or hypersaline origin in the lower half of the Purbeck, is described in detail. The species differs from known members of the Pholidophoridae in a number of characters, especially in the structure of the snout, and a new family Ichthyokentemidae is made to contain it. Variations in the structure of the snout in halecostomes are shown to separate the group into at least two lines which may be only distantly related. The origin of the halecostomes is to be found near the Parasemionotidae. but it is considered that the parasemionotids are unlikely to have been directly ancestral to the group because of the structure of their neurocrania. The evolution of the fossa bridgei is discussed, and it is concluded that the post-temporal fossa of holosteans and teleosts is not homologous with the fossa bridgei, but is a new structure which has replaced the latter. [end of synopsis]
    Example extracts regarding the location: "In 1958 and 1959 the authors and Dr. B.G. Gardiner collected a large number of disarticulated fish bones from the Lower Purbeck Broken Beds near Lulworth Cove, Dorset...... At Lulworth there is a 6-in. band of yellow-brown, sandy limestone, darker in colour than the surrounding purer limestone, lying about 6 ft. 3 in. below the top of the Broken Beds. Eight inches below this band there is a similar band, 3 to 5 in. thick. The fishes were found in the 3 ft. 6 in. of limestone directly below this band. The specimens were collected from a single large block, about I0 ft. long and 4 ft. thick, lying immediately above the" fossil forest" where it is exposed in the cliff a quarter of a mile east of the mouth of Lulworth Cove. The bones were distributed throughout 3 ft. 6 in. of sediment, and were common everywhere, though more abundant in and near the clay partings which occur irregularly in the rock. The fish remains are all disarticulated, only the neurocrania, mandibles and pectoral girdles being preserved reasonably intact. Though the bones lie scattered throughout the rock, they are perfectly preserved, and show no signs of rolling or abrasion. There are some signs that the bones have been water sorted, for while no specimen shows scattered remains of a single skeleton, it is common to find two or three neurocrania lying close together with no other bones in their vicinity. The vast majority of the bones are of Ichthyokentema purbeckensis : we have parts of at least 50 neurocrania of this species. A few fragments of other fishes are present, including a maxilla, a preoperculum, a hyomandibular, a dentary, an angular, vertebrae and scales of a leptolepid, scales and teeth of a holostean and some undetermined teeth. Associated with the fishes are fragmentarv plant remains and abundant ostracods ... "[continues - see full paper for more information]
    Grocke , D., Hesselbo, S.P. and Jenkyns, H.C. 1999. Carbon-isotope composition of Lower Cretaceous fossil wood: ocean-atmosphere chemistry and relation to sea-level change. Geology, 27, 155-158.

    Grocke, D. R., Price, G. D., Ruffell, A. A., Mutterlose, J. and Baraboshkin, E. 2003. Isotopic evidence for Late-Jurassic - Early Cretaceous climate change. Palaeogeography Palaeoclimatology Palaeoecology, 202, 97-118.
    Groves, J. and Bullock-Webster. 1924. British Charophyta. Book. Ray Society, London.

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    Haggart , J.W., Matsukawa, M. and Itoc, M. 2006. Paleogeographic and paleoclimatic setting of Lower Cretaceous basins of East Asia and western North America, with reference to the nonmarine strata. Cretaceous Research, 27, April 2006, pp. 149-167.
    Abstract: Lower Cretaceous strata are widespread in East Asia and along the western coast of North America. In both regions, Cretaceous basins contain significant stratigraphic accumulations and can be thought of as along-strike equivalents. In East Asia, fore-arc basins were oriented parallel to and east of active magmatic arcs while in western North America extensive fore-arc successions accumulated west of the arc complexes. The greater extent of nonmarine, rift and back-arc basins in the East Asian region, and overall lower topographic development, was likely related to movement of the region away from ongoing subduction to the east. In western North America, by contrast, movement of the North American plate westwards towards the active subduction zone resulted in development of a volumetrically larger and topographically higher orogen than in East Asia.
    The active arc complexes in both regions exerted significant controls on paleoclimate. Interior basins of both Asia and North America, landward of arc complexes, were significantly drier than the coastal areas, due to rain-shadow phenomena in both regions. Although the proto-Pacific Ocean was likely much wider during Early Cretaceous time than it is today, we infer that similar oceanic circulation patterns existed and significantly affected climate and molluscan biogeographic assemblages of both East Asia and western North America: East Asia was dominated by warm water derived from the Tethyan regions, whereas west coast North America was influenced by cooler waters derived from high-latitudes.
    Hallam , A. 1993. Jurassic climates as inferred from the sedimentary and fossil record. Philosophical Transactions of the Royal Society of London, Series B, 341, 287-296.
    Hard, W.M. 1910. Old Swanage or Purbeck Past and Present: A Collection of Articles, Topographical, Historical, Antiquarian, Biographical and Anecdotal. New and Revised Edition with Three Supplementary Chapters. Twenty-eight full page illustrations, including reproductions of rare prints. Dorchester, "Dorset County Chronicle" Printing Works. 264pp. Original price 3 shilling and 6 pence. By William Masters Hardy, author of "Smuggling Days in Purbeck" etc. [A good publication on the history of Swanage and adjacent area, including accounts of quarrying of Portland and Purbeck Stone within the Isle of Purbeck. Not strictly geological.]
    Harland , W.B. et al. 1967. The Fossil Record: A Symposium with Documentation. Geological Society of London, London, 827p.
    Harris , T.M. 1939. British Purbeck Charophyta. British Museum (Natural History). London, Printed by Order of the Trustees of the British Museum, Issued April 22nd, 1939. 83 pp + 17 plates. Hard-cover. [by Professor Thomas Maxwell Harris, Professor of Botany in the University of Reading - Professor Tom Harris was well-known for his studies of Middle Jurassic plants].
    Hawkins , H.L. 1925. On Echinoidea from the Portland Stone and the Purbeck Beds. Quarterly Journal of the Geological Society, London, 81, cxxxviii. [Note on the finding by Professor Hawkins, of Reading University, of thirty-eight tests of the Jurassic-type echinoid Hemicidaris purbeckensis in the Cinder Bed of Durlston Bay, Dorset.]
    Heap , W., 1957. The Mammal Bed of Durlston Bay. The Dorset Year Book, 1957-8, pp. 83-85. [Mr. Heap found Beccles Mammal Pit and Willett's Mammal Pit at the cliff top. He discovered four mammal jawbones in the cliff exposure at the beach south of the Zigzag Path.]
    Hesselbo , S.P. 1988. Sequence boundaries in the basal Wealden Beds ( Lower Cretaceous; Wessex Basin) at Mupe Bay, Dorset. B.S.R.G. - British Sedimentological Research Group, 1988, Cambridge, no page numbers. [Two erosion surfaces are angular unconformities - one is the palaeo-oil seep -fluvial above]

    Hesselbo, S.P. and Allen, P.A. 1991. Major erosion surfaces in the basal Wealden Beds, Lower Cretaceous south Dorset. Journal of the Geological Society, London, 148, (1) 105–113. By Stephen P. Hesselbo and Phillip A. Allen, Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR UK. Abstract: The transition from evaporitic and lagoonal Purbeck Beds into the fluviatile basal Wealden Beds (Ryazanian-Valanginian) has in the past been interpreted as a continuous regressive succession. Mupe Bay and Bacon Hole, in south Dorset, are the only localities in the Wessex Basin of southern England at which the transition strata are well exposed and not extensively faulted. On the basis of facies analysis the lowermost Wealden Beds are interpreted as a regressive-transgressive-regressive package. Environments fluctuated between lagoon, inner-lagoonal shoreline and fluvial flood plain. The overlying succession is remarkable for the presence of two major erosion surfaces which, based on field geometries and fades relationships, are interpreted as unconformities. The lower unconformity is overlain at Mupe Bay by sediments of lagoonal or lacustrine origin. The upper unconformity is expressed as the celebrated Mupe Bay palaeo-oilseep, an oil-cemented conglomeratic sand, overlain by a thick succession of fluvial sediments. A level near the basal sand and the two erosion surfaces are treated as candidate sequence boundaries (WBI-WB3), with the thin intervening ?lagoonal deposits representing peaks of transgression. The pattern of one minor (conformable) sequence boundary followed by two major (unconformable) sequence boundaries bears a strong resemblance to the Early Cretaceous sequence stratigraphy suggested in recent 'global cycle charts'. However, biostratigraphical calibration of the sections is currently inadequate to allow close correlation with candidate sequence boundaries in other areas. [Comments: They discussed the origin of the conglomeratic oil sand at Mupe Bay. They recognised unconformities and have considered these as candidates for major subdivisions within the Wealden. Two major erosion surfaces at Mupe Bay, one the celebrated oil sand channel, are interpreted as unconformities. These authors attempt to establish a sequence correlated with Early Cretaceous sequence stratigraphy suggested in recent global cycle charts. The authors also comment, that subsidence histories and stratal geometries show that the main extensional activity on the fault system took place in early Jurassic and late Jurassic/early Cretaceous times and that the faults are probably active throughout deposition of the Purbeck and Wealden Beds. They record soft sediment deformation at Mupe Bay.]
    Hinde, G.J. 1893. British Fossil Sponges, Monograph of the Palaeontographical Society, vol. 1, p. 212, plate 13, fig 6 - Spongilla purbeckensis Young. This is the only known British Jurassic Monactinellid sponge, according to Arkell (1953). However, Clements (1967) considered that the supposed monactinellid sponge spicules are not fossil at all but are actually the common silica pseudomorphs after lenticular crystals of gypsum, that were described in West (1964).
    [See also Young (1878). See also Hinde - Catalogue of the Sponge in the British Museum.]
    Hinton , D.A. 2002. Purbeck Papers. [On archaeology of the Isle of Purbeck, not on the Purbeck Group; however with much reference to Purbeck Marble etc.] University of Southampton, Department of Archaeology, Monograph No. 4., Oxbow Books, 144pp. Edited by David A. Hinton. See also: Purbeck Papers archaeological website.
    From the back cover: "The Purbeck peninsula in south-east Dorset is noted for its varied geology, which has led to the development at various times of different crafts and industries, as well as a range of agricultural practices. This monograph describes excavation, historical research and fieldwork undertaken by the Department of Archaeology, University of Southampton, supported by English Heritage, in the 1990s. The papers are an excavation report on an Iron Age and Romano-British complex which included an exceptionally well-preserved roundhouse and field-barn with grain-drier; a study of Purbeck's society and economy in the early Middle Ages, and publication of some of the relevant documents; a review of the Marble industry in both the Roman and medieval periods; survey of the famous strip Iynchets overlooking the sea at Worth Matravers; and an examination of their use and abandonment."
    Graham, A.H., Hinton, D.A. and Peacock, D.P.S. 2002. The excavation of an Iron Age and Romano British settlement in Quarry Field, south of Compact Farm, Worth Matravers, Dorset. pp. 1-83.
    Hinton, D.A. 2002. A 'marginal economy'? The Isle of Purbeck from the Norman Conquest to the Black Death. pp. 8-117.
    Rushton, N.S. 2002. Some pre-Black Death surveys and extents of Purbeck. pp. 118-125.
    Williams, D.F. 2002. Purbeck marble in Roman and medieval Britain. pp. 126-131. [See separate reference below: - Williams, (2002)]
    McOmish, D. 2002. Report on the strip lynchets at Worth Matravers, Dorset. pp. 132-138.
    Hinton, D.A. and Trapp, H. 2002. The Worth Matravers strip fields in the eighteenth century. pp. 139-144.
    Holliday , D.W. 1970. The petrology of secondary gypsum rocks: a review. Journal of Sedimentary Petrology, 40, 734-744. [Purbeck gypsum]

    Holliday, D.W. 1973. Early diagenesis in nodular anhydrite rocks. Transactions of the Institute of Mining and Metallurgy, vol. 82, pp. B81-84.

    Holliday, D.W. and Shephard-Thorn, E.R. 1974. Basal Purbeck Evaporites of the Fairlight Borehole, Sussex. Institute of Geological Sciences [now British Geological Survey], Natural Environment Research Council. Her Majesty's Stationery Office. Report No. 74/4, 14pp. with fold-out graphic log of the basal Purbeck evaporites of the Fairlight Borehole.
    Hollingworth , S.E. 1938. The Purbeck Broken Beds. Geological Magazine, 75, 330-332. [Professor Hollingworth was the first to suggest that evaporites were once present at the horizon of the Broken Beds in the Purbeck Group. This was later confirmed by the petrographic studies of Ian West.]
    Horne , D.J. 1988. Cretaceous ostracoda of the Weald. British Micropalaeontological Society Field Guide, 4, 42pp.

    Horne, D.J. 1995. A revised ostracod biostratigraphy for the Purbeck-Wealden of England. Cretaceous Research, 16, 639-663, Academic Press Ltd. By David J. Horne. Department of Earth and Environmental Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB.
    Abstract: The extensive work of the late F.W.Anderson on Purbeck-Wealden ostracods is critically reviewed. He used ostracods as the basis of four different kinds of stratigraphical subdivision in the English Purbeck-Wealden sequence: zones (based on the ranges of Cypridea species), faunicycles (based on alternations of assemblages dominated by Cypridea with assemblages dominated by other genera), 'beds' and 'assemblages' (both groupings of faunicycles). It is concluded that although Anderson's own correlations using these schemes might be regarded as reliable, all of them were so poorly defined as to preclude their use by future workers. Furthermore, erroneous zonation schemes have been propagated by other authors who mistook Anderson's assemblages for zones. In spite of criticisms of his applications and interpretations of ostracods, Anderson's data remain the best available for the Purbeck-Wealden of the Weald and Wessex sub-basins. As a solution to some of these problems, a new ostracod biozonation scheme is proposed, comprising three zones (Theriosynoecum forbesi Zone, approximately equal to the Purbeck; Theriosynoecum alleni Zone, approximately equal to the Hastings Beds Group; Theriosynoecum fittoni Zone, approximately equal to the Weald Clay Group), subdivided into eight subzones on the basis of the ranges of Cypridea species. [end of abstract] [Comments by Ian West: A very good paper with amongst other topics (which includes important zonal schemes), a sensible and realistic assessment of F.W. Anderson's ostracod work and his faunicycles. Many Purbeck workers have probably found these "cycles" potentially valuable but difficult to use in practice. Anderson in (1932) started his studies of ostracods and cyclicity in the Middle Purbeck Beds of Durlston Bay. Later he worked extensively with boreholes. For those involved with Durlston Bay it has been difficult to fix his faunicycles well, because of lack of precise ostracod sample data. Anderson's basal Purbeck work in Dorset was sketchy, largely because of hypersaline facies and lack of low salinity ostracods. It does not tie in with detailed petrographic studies of these beds (West, 1975). Amongst other things, this recent paper by Horne with its reassessment of Anderson's work much facilitates the understanding of the faunicycles.]
    Horton , A, Sumbler, M G, Cox, B M, and Ambrose K. 1995. Geology of the Country around Thame. Memoir of the British Geological Survey, Sheet 237 (England and Wales). Her Majesty's Stationery Office, London. 169 pp. Contributors: A.J.M. Barron, A. Forster, R.D. Lake, M.D. A. Samuel, M.A. Woods, J.M. Allsop, H.C. Ivimey-Cook, R.J. Wyatt, C.S. Cheney, C.J. Wood, P. Allen, A. Parker. Example extract from the beginning - pp. 1-2: Introduction: The memoir describes the geology of the Thame district, which is covered by 1:50000 Geological Sheet 237. The west and south-western part of the district lies in Oxfordshire and includes both the eastern suburbs of the city of Oxford and the ancient market town of Thame. The remainder lies in Buckinghamshire and includes much of Aylesbury (the county town) and Princes Risborough. Outside these main conurbations, the district is mainly rural, with many small and picturesque villages. The rocks which crop out in the district are of Jurassic and Cretaceous age. They comprise alternating units of more and less resistant strata which, in general, dip very gently (approximately half to one degree) towards the south-east. The physiography of the district is dominated by clay lowland, lying mostly at less than 80m above O.D. This is divided into two northeastward-trending vales separated by a range of hills capped by the limestones and sands of the Corallian, Portland, Purbeck and Whitchurch Sand formations, which cross the district diagonally from near Oxford to Aylesbury. North-west of the hills, the vale of the River Ray is formed by the Kellaways, Oxford Clay and West Walton formations. To the south-east, the vale of the River Thame is cut mainly into the mudstones of the Ampthill Clay, Kimmeridge Clay and Gault formations. The latter forms the so-called Vale of Aylesbury, bounded to the south by the steep Chalk escarpment of the Chiltern Hills, which reach 244 m above OD [773 008], near Chinnor. Both the Ray and Thame are tributaries of the River Thames which flows across the extreme south-west corner of the district...[continues].

    Example extract on the Purbeck Group (part of p.79; Purbeck is from p. 79 to 83 and is preceded by a relevant section on the Portland): The Purbeck Group comprises limestones, interbedded with marls, clays and sandy clays, and the outcrop is characterised by a brashy, dark brown clay soil. Up to 6 m of strata are preserved near Haddenham and Stone; a slightly thicker succession (about 6.6 m) recorded at Whitchurch just outside the district (Barker, 1966) is the maximum known in the region. The most typical rock type is a white micrite limestone (lime mudstone), generally massive, but in some cases showing algal laminae or stromatolitic structure. These limestones are commonly brown mottled, and are intensely hard and splintery, due to recrystallisation. Bored bedding surfaces, indicating penecontemporaneous cementation, are common. Syneresis (shrinkage) cracks, fenestrae ('birds-eyes') and, more rarely, mud cracks and possible salt pseudo morphs also occur, and indicate periods of subaerial emergence. At some localities, sandy, peloidal or oolitic limestones have been recorded but, in general, such higher energy facies are rare. Virtually all recorded sections through the formation indicate laminated marls and limestones in the lowest part. Such limestones at this level have traditionally been known as the 'Pendle' (Fitton, 1836; Morris, 1856; Jones, 1885), which typically comprises alternating laminae (up to 10 mm thick) of shell-fragmental, commonly sandy, ostracod-rich limestone (packstone to grainstone), and pure micrite (lime mudstone). The 'Pendle' locally up to 0.5 m thick, forms a useful marker at or just above the base of the formation. As in the type area of Dorset, the junction with the underlying Portland Formation is gradational, and differentiation of the two formations depends on recognition of predominantly nonmarine lithofacies and fauna in the Purbeck, in contrast to the marine aspect of the Portland. Traditionally, therefore, the base of the formation has been drawn at the base of the 'Pendle' which is 'the first occurrence of a bed in which large molluscan macrofauna is absent, and fine regular lamination is well developed' (Radley, 1991). However, during this survey, it was found more practical to define the base of the formation at the top of the massive, marine limestones of the Portland Formation. Although these two horizons are coincident in many places, at others (including the Hartwell and Brill No. 1 boreholes), up to 0.5 m of shelly marl with' Ostrea' expansa and other large bivalves, intervenes between the Portland Formation and the 'Pendle'. This 'Upper Shell Marl' was included in the Portland Formation by Bristow (1968) and Radley (1991).... [continues]

    To purchase the Thame memoir go to:
    BGS Online Bookshop. The price given in 2005 is 55 pounds. The associated Thame geological map sheet 237 is 11 pounds.

    [To avoid confusion, note that - Sherlock, R.L. 1922, The Geology of the Country around Aylesbury and Hemel Hempstead. Memoirs of the Geological Survey, does not cover the same area. It is for sheet 238. This is the country further east and this old memoir does not have a section on the Purbeck Group. Aylesbury is at the boundary between the two maps.]
    Howitt , F. 1964. Stratigraphy and structure of the Purbeck inliers of Sussex (England). Quarterly Journal of the Geological Society, London, 120, 77-113. By Frank Howitt. Published 18th February 1964. With maps and a discussion.
    Abstract: The Purbeck Beds exposed in Sussex are redescribed together with new sections exposed in gypsum mine workings and boreholes. Comparisons are made with Purbeck Beds elsewhere in southern England in boreholes and at outcrop. A new map of the the Purbeck inliers is presented and the structure is discussed. Conditions of sedimentation are illustrated by isopachyte maps.
    1. Introduction
    2. Historical Review
    3. Stratigraphy
    (a) General
    (b) Sussex type area
    (c) Comparison of the Sussex Purbeck type-sections with the remainder of the Sussex inliers
    4. Structure
    5. Conditions of sedimentation
    6. Appendix: Purbeck Beds in boreholes and outcrops of southern England.
    7. References
    Plates 3-4, Geological Map and Structural Map - Central Weald.
    House, M.R.

    The Late Professor Michael House The late Professor Michael House, author of well-known guides to the geology of the Dorset Coast, and former Professor of Geology at Hull University and at Southampton University. He was most notable as a Devonian specialist but was very much involved in research and publication on the Jurassic and Cretaceous of the Dorset coast, his home region. His guides are excellent, thorough and accurate summaries of Dorset geology.

    House, M.R. 1958. The Dorset Coast from Poole to the Chesil Beach. Geologists' Association Guides, No. 22, 21pp.

    House, M.R. 1966. Purbeck Beds [Note on Pseudomorphs after Halite]. Proceedings of Dorset Natural History and Archaeological Society, vol. 87, pp. 33-34. Natural History Reports for 1965. [Reproduced in full below].
    Salt pseudomorphs are common on certain bedding planes in the Lower Purbeck Beds. In the Lulworth District they were recorded by H.W. Bristow an W. Whitaker on their Vertical Sections of the Purbeck Strata of Lulworth, Dorset (1859, Sheet 56, Horizontal Sections, Geological Survey) and by H.B. Woodward, The Jurassic Rocks of Britain, vol. 5, (1895, p. 244), particularly in the Soft Cockle and Hard Beds [Members].
    In the section at present visible above the Fossil Forest, there is a distinctive layer of pseudomorphs 21 ft. (6.4m.) above the top of the Broken Beds, that is, at 3ft (0.9) metres above the top of the Cypris Freestones. The bed is 1 inch to 5 inches (2.5cm to 12.7cm) in thickness, and is a pellet limestone with marl and marly clay horizons above and below. Salt pseudomorphs [natural casts], some with clear Hopper crystal faces, project both above and below the surface of the bed but are commonest on the lower surface. Thin sections show no evidence of pseudomorphs within the bed, and the pseudomorphs [halite casts] are full of pellets in continuity with those that comprise the bed. The origin of the bed presents a problem in view of the occurrence of pseudomorphs [halite casts] on both surfaces of the bed. Faecal pellet limestones of this sort are not uncommon at the present day and may be formed by a number of organisms, but especially crustacea. On the interpretation favoured here, a bed of unconsolidated pellets, overlain and underlain by marly clay became the site of halite crystallisation. Large crystals are know to form today just below the sediment/water interface. In this case they appear to have formed especially at the marl/pellet interface. Subsequently the marl on either side hardened forming a mould of the crystal and bed surface, the pellets remained uncemented and the crystals unchanged. At a later stage the salt was removed in solution and the superincumbent pressure condensed the bed packing the pellets above and below to fill the external moulds of the crystals still remaining in hardened clay-marl on either side.
    One specimen from this locality, now presented to our Museum, has a surface area of 98 square centimetres with 59 halite crystal pseudomorph cubes clear enough to measure upon one surface (the lower). The sides of the cubes range from 2 to 18mm. The total volume of the cubes represented on this surface is is about 25cc. This is the equivalent of 54 grams of salt, or to the salt contained in two litres of seawater. It may be that this is the measure of an influx of salt water which, on subsequent desiccation, produced the halite on the lower surface. That desiccation occurred is also shown by the fact that desiccation cracks in the marl on either side of the bed have been penetrated in places by pellets forming small dikes. Probably this occurred at the time of the infilling and packing of the crystal moulds for they in places are confluent with them. [end of short note]

    House, M.R. 1968. Purbeckian calcareous algae. In Dorset Natural History Reports - 1967 - Geology. Proceedings of Dorset Natural History and Archaeological Society for 1967. vol. 89, p.41-45.

    House, M.R. 1970. The Portland Stone on Portland. Proceedings of Dorset Natural History and Archaeological Society, 91 (for 1969), 38-39.

    House, M.R. 1989. Geology of the Dorset Coast. Geologists' Association Guide, 169pp, 39 text-figs and 34 monochrome plates. September 1989. Paper-back. ISBN 0 7073 0485 7.

    House, M.R. 1993. Geology of the Dorset Coast. Geologists' Association Guide No. 22. 2nd edition, 164pp., 43 text-figs (mostly cliff diagrams and maps) and 32 plates, some in colour. Paper-back. ISBN 0 7073 0485 7. Extract from Preface: "This guide aims to provide a general introduction to what may may be seen and where. Emphasis is placed on the localities and the precise discrimination of the stratigraphic successions. It is hoped that in this way new observations can be better integrated with earlier work and thus form a more scientific basis for individual study, thought and interpretation and argument. Most emphasis is placed on the Jurassic rocks because these are such an international standard. Rather less detail is given on the Cretaceous and Tertiary rocks because these rocks are as well or better seen elsewhere, and the Dorset Chalk cliffs, being mostly vertical, are also dangerous. In any case, with such a wealth of geology to describe, some selection has been essential. The introductory sections on Sedimentology and Palaeontology have been added by request to introduce specialist terms to the general reader. "

    Huckreide, R. 1967. Molluskenfaunen mit limnischen und brackischen Elementen aus Jura, Serpulit und Wealden NW-Deutschlands und ihre palaeogeographische Bedeutung. Beih. geol. Jb., Vol. 67, 263pp. [Molluscan fauna with limnitic and brackish elements from the Jurassic Serpulit and Wealden of NW Germany and their palaeogeographic significance.]
    Hudleston, W.H. 1881. Notes on some gastropods from the Portland Rocks of the Vale of Wardour and Buckinghamshire. Geological Magazine, series 2, , vol. 8, p. 385.
    Hughes T. 2003. Stone roofing in England. Pp. 32-127, in: Wood, C. 2003. Stone Roofing: conserving the materials and practice of traditional stone slate roofing in England. Edited by Chris Wood, English Heritage Research Transactions, Volume 9, August, 2003. 156 pp. James and James (Science Publishers) Ltd., Camden High Street, London. ISBN -1-902916-32-8. Stone Roofing in England - by Terry Hughes, Slate and Stone Consultants, Ceunant, Caernarfon.
    Abstract: Following the study of the stone slate industry and market in the South Pennines, the situation for the rest of England was researched. The historical sources of stone slates and their geology are reviewed and the challenges to the continued regeneration of stone slate delving are discussed. The current state of supply and demand in the conservation of stone slated buildings is assessed.
    [On p. 47 the section on "The Isle of Purbeck and Portland" commences. Table 6 on p. 48 gives "Approximate alignment of historical and modern 'Purbeck Bed' names. The section regarding the Purbeck continues to p. 52. There is much information in this very comprehensive paper on other Mesozoic roofing slates, such as those from the Forest Marble.]
    Hulke , J.W. 1878. Note on two skulls from the Wealden and Purbeck Groups indicating a new Sub-group of Crocodilia. Quarterly Journal of the Geological Society, London, 34, 377-382.
    Hunt , C.O. l985. Miospores from the Portland Stone Formation and lower part of the Purbeck Group ( Upper Jurassic/Lower Cretaceous) from Dorset, England. Pollen et Spores, 27, 4l9-45l.

    Hunt, C.O. 1987. Dinoflagellate cyst and acritarch assemblages in shallow-marine and marginal-marine carbonates: the Portland Sand, Portland Stone, and Purbeck Groups (Upper Jurassic/Lower Cretaceous) of southern England and northern France. In: Micropalaeontology of Carbonate Environments (ed. Hart, M.B.), pp. 208-225, Ellis Horwood, Chichester. [Hunt placed the Jurassic/Cretaceous boundary just above the base of the "Cypris " Freestones, on the basis of palynomorphs. This is supported by Feist et al., 1995).]
    Hunter , S. 1967. Pardon, old thing, but your slip is still showing. Glasgow Herald, Newspaper, 13 March 1967, p. 8. "Iguanodon did stagger 120 million years ago and this morning geologists at Glasgow University have the scoop of the story of where he slipped. At the Hunterian museum they to-day uncovered a 21 feet (6.4 m) limestone track where a dinosaur walked - the first indoor exhibition of any such track in Britain. .. Dorset quarrymen found the prints [in Suttle's Quarry in 1962]. The two-ton track was then lifted from the Middle Purbeck beds and crated in pieces to Glasgow. .. He (she?) swivelled rather at the hips and put the feet down almost in line. This kind of mannequin movement involves some rotation of the foot at the ankle and would produce a smudged impression on a slippery surface. So the blurred fourth footprint of the Hunterian slab marks the spot where Iguanodon skidded in the mud." [Article written in 'popular' style by Samuel Hunter. The footprints are probably not of an Iguanodon. See Charig and Newman (1962) and other articles listed here.

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    International Commission on Zoological Nomenclature 2001.General articles and nomenclatural notes. BZN, vol. 58, pt. 3, 28 Sept. 2001. Also available online.
    PALUDINIDAE INDEX: (Opinion 573, 1959) Gray, 1840, Synopsis of the contents of the British Museum. Ed. 42: 117. CORRECTION: Fitzinger, 1833, Beitrkge zur Landeskunde Oesterreich's unter der Enns, 3: 109 (as `Gruppe' Paludinoidea). First used as the vernacular `Les Paludinides' by Risso, 1826, Histoire Naturelle ... de 1'Europe Meridionale, 4: 100, but there is no current usage to attribute the name to Risso. PALUDINIDAE is based on the name Paludina Ferussac, 1812 (a junior objective synonym of Viviparus Montfort, 1810).
    [This is not specifically on the Purbeck Group, but it helpfully explains why the pondsnail of the Purbeck Marble is referred to the genus Viviparus and not Paludina as it once was.]

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    Jarzembowski , E.A. 1993. A provisional checklist of fossil insects from the Purbeck Beds of Dorset. Proceedings of the Dorset Natural History and Archaeological Society, vol. 114 for 1992. Over 120 species of insects are known from the Dorset Purbeck; the fauna is listed and a selection is illustrated photographically.

    Jarzembowski , E.A. 1995. Early Cretaceous insect faunas and palaeoenvironment. Cretaceous Research, 16, 681-694. [Notes: Warmer conditions are indicated by many species of Blattoidea. Lepidoptera were beginning at this time.]

    Jarzembowski, E.A. 1996. Towards a revision of Purbeck insects: Protogryllus, Panorpidum, Pleciomyia and Prohousea Nom. Nov. Proceedings of Dorset Natural History Archaeological Society, for 1995, vol 117, 155-157.

    Jarzembowski, E.A. and Coram, R. 1997. New fossil insect records from the Purbeck of Dorset and the Wealden of the Weald. Proceedings of Dorset Natural History and Achaeological Society, for 1996, vol.118, 119-124. Authors' Abstract: This paper updates the checklist (Jarzembowski, 1993) and subsequent articles (Clifford et al. 1994; Coram et al. 1995) in previous Proceedings. Recent discoveries are reviewed and Purbeck fossil insects collected by the Revd O. Fisher last century and deposited in the Sedgwick Museum, Cambridge, have been re-examined. Some groups are traced through the non-marine Lower Cretaceous of southern England. (End of Authors' abstract). [Bugs, flies etc from the Middle Purbeck of Durlston Bat and dragonfly larvae from the Lower Purbeck of Durlston Bay and Freshwater Bay, Portland.]

    Jarzembowski, E. A, Martinez-Delclos, X., Bechly, G., Nel, A, Coram, R. and Escuillie, F. 1998. The Mesozoic non-calopterygoid Zygoptera: description of new genera and species from the Lower Cretaceous of England and Brazil and their phylogenetic significance (Odonata, Zygoptera, Coenagrionoidea, Hemiphlebioidea, Lestoidea). Cretaceous Research, 19,403-444.
    Jimenez de Cisneros , C. and Vera, J.A. 1993. Milankovitch cyclicity in Purbeck peritidal limestones of the Prebetic (Berriasian, southern Spain). Sedimentology, 40, No. 3, June, 1993, pp 513-539. [Notes: Milankovitch cycles found by Fast Fourier Transform. Cycles are mainly about 40,000 year Milankovitch obliquity cycles. Role of glacio-eustasy - see also Frakes and Francis 1988, Nature. Cyclic carbonate deposition. Sierra del Pozo region, southeast Spain, near the coast, north-east of Granada. Black pebbles. Evaporites. Birdseyes. Del 13C and del 18 O isotope data. Sr ppm. Sr high in subtidal facies. Sedimentation rate 12-15 cm per 1000 yrs (ie. about 0.13 mm per annum).]
    Jones , T.R. 1878. Notes on some fossil bivalved Entomostraca: iv. Geological Magazine, (2), vol. 5, 103-110, 277-278. [Purbeck and Wealden ostracods.]

    Jones, T.R. 1885. On the Ostracoda of the Purbeck Formation; with notes on the Purbeck species. Quarterly Journal of the Geological Society, vol. 50, pp. 156-168.

    Jones, T.R. 1890. On some fossil Estheriae: B. Purbeck Estheriae. Geological Magazine, vol. 7, 385-390. [Euestheria]

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    Kamerling , P. 1979. The geology and hydrocarbon habitat of the Bristol Channel Basin. Journal of Petroleum Geology, 2, 75-93. Purbeck and Wealden.
    Kear, B.P., Milner, A.R. and Barrett, P.A. 2009. Plesiosaur remains from the Jurassic-Cretaceous Purbeck Limestone Group of southern England.Proceedings of the Geologists' Association, London, Vol. .., article in press. Available online 9 July 2009.
    Plesiosaur fossils from the uppermost Tithonian (Upper Jurassic) to lower Valanginian (Lower Cretaceous) Purbeck Limestone Group of Dorset, England are important because they constitute a rare record from around the Jurassic-Cretaceous boundary. Where diagnostic, the remains are referred to indeterminate plesiosauroids (Cryptocleidoidea) and represent relatively small animals including a previously undescribed juvenile individual. This observation accords with the lagoonal-lacustrine (with periodic marine influx) depositional setting of the Purbeck Limestone Group strata, a palaeoenvironment that is often associated with juvenile plesiosaur occurrences.
    1. Introduction
    2. Systematic palaeontology
    2.1. Referred material
    2.2. Description
    3. Comparisons and discussion
    Fig. 1. Locality maps showing (A) geographic positions of the Isle of Purbeck/Isle of Portland (rectangle) in the British Isles and (B) outcrops of the Purbeck Limestone Group rocks in Dorset (after Underhill, 2002). Lithostratigraphic framework and age correlations of the Purbeck Limestone Group are also provided together with a simplified lithological column indicating provenance of the plesiosaur fossils (table modified from Ensom et al., 2009; lithostratigraphic terminology after Westhead and Mather, 1996; after Clements, 1993).
    Fig. 2. Potentially associated juvenile plesiosauroid (Cryptocleidoidea) remains from the Purbeck Limestone Group. Posterior cervical vertebral centrum (NHM R6412) in anterior (A), ventral (B) and lateral (C) views. Limb girdle fragment NHM R6410 in planar (D) and transverse (E) views. Propodial (NHM R6409) in ventral (F) and posterior (G) views. Scale bars 20 mm in (A)–(E); 40 mm in F and G.
    Fig. 3. Various plesiosaur fossils from the Purbeck Limestone Group. Incomplete propodial (NHM 21974) in dorsal (A) view. Propodial (BGS 87565) in dorsal (B) view. Cryptocleidoid cervical vertebral centrum (NHM R1607) in lateral (C) and anterior (D) views. Cryptocleidoid dorsal vertebrae with associated limb girdle fragments (BORNH 0717a; E) and cervical vertebral series (BORNH 0717f; F) in lateral view. Scale bars 50 mm in A and B; 40 mm in C-F.

    Kendall, C,G.St.C. and Alsharhan, A,S. (Editors) 2011. Quaternary Carbonate and Evaporite Sedimentary Facies and Their Ancient Analogues: A Tribute to Douglas James Shearman. Special Publication No. 43 of the IAS, International Association of Sedimentologists. John Wiley and Sons, 25th January 2011, 495pp. This volume commemorates the eclectic research of Douglas James Shearman into evaporites, which was initiated by his studies of the prograding UAE coastal sabkhas or salt flats that incorporate evaporite minerals which displace and replace earlier carbonate sediments. His subsequent proselytization of the study of ancient evaporites in sedimentary sections all over the world led to fundamental advances in our understanding of arid zone carbononate sedimentology. [continues]

    [This large and important book is not cheap; it costs beteen about 58 to 75 pounds stirling at various book sellers, in late 2011. Extracts can be seen online at Google Books - Kendall and Alsharhan.].
    Kielan-Jaworowska , Z., and Ensom, P.C. 1992. Multituberculate mammals from the Upper Jurassic Purbeck Limestone Formation of southern England. Palaeontology, 35, 95-126. [Mammal horizons above the Mammal Bed and equivalent to bed DB 102 of the Cherty Freshwater Member. Very small teeth separated by sieving.]

    Kielan-Jaworowska, Z. and Ensom, P.C. 1994. Tiny plagiaulacoid multituberculate mammals from the Purbeck Limestone Formation of Dorset, England. Palaeontology, 37, 17-31. [Sunnydown Farm, Cherty Freshwater Member, Langton Matravers, rodents, sieved sediments.]

    Kielan-Jaworowska, Z. and Hurum, J.H. 2001. Phylogeny and systematics of multituberculate mammals. Palaeontology, 44, 389-429. Abstract: We present a synopsis of high-rank multituberculate systematics and a manually generated cladogram illustrating multituberculate interrelationships. We divide the Multituberculata into the paraphyletic suborder 'Plagiaulacida', an apparently monophyletic suborder Cimolodonta, and one family incertae sedis. Within 'Plagiaulacida' we recognise three informal lines: paulchoffatiid (three families), plagiaulacid (three families) and allodontid (two families and the genus Glirodon). The Cimolodonta are divided into an informal Paracimexomys group; three superfamilies: Ptilodontoidea, Djadochtatherioidea (new), and Taeniolabidoidea (restricted to Taeniolabididae); and five families (superfamily incertae sedis): Eucosmodontidae, Microcosmodontidae, Cimolodontidae, Boffiidae, and Kogaionidae; and some genera incertae sedis. New characters used in our analysis are (1) a tendency of molar cusps to coalesce; and (2) ornamentation of grooves, pits, and ridges on the molars. We argue that the Ptilodontoidea, and less certainly also the Cimolodontidae and Boffiidae, might have originated from among the plagiaulacid Line, a possible intermediate link being the Paracimexomys group. The remaining Cimolodonta might have originated from unknown members of the Paracimexomys group with separated molar cusps and smooth enamel. The origin of two types of prismatic enamel and a relationship between them are stumbling blocks in understanding the origin of the Cimolodonta; we conclude that microprismatic enamel made its appearance only once. Revised diagnoses of high-rank multituberculate taxa, including lists of all known genera, are given.
    Kilenyi , T.I. and Neale, J.W. 1978. The Purbeck/Wealden. In: A Stratigraphic Index of British Ostracoda. (Eds. Bate, R.H. and Robinson, J.E.), Geological Journal, Special Issue, 8, 299-324.
    Kingsley , C. 1857. Geological Discoveries at Swanage. Illustrated London News, Dec. 26th 1857, pp. 637-638. [With classic etching of Beccles Mammal Pit.]
    Kuban, G.J. 1994-210. An Overview of Dinosaur Tracking. Webpage. - go to website. By Glen J. Kubab.
    Example extract:
    "There are two main ways in which tracks can be formed and preserved. The classic scenario is as follows. First, a trackmaker walks along a moist but firm, fine-grained sediment. Then the tracks remain exposed for a short while, allowing them to become drier and harder (and thus able to resist damage during subsequent burial). A short time later the prints are gently buried with additional sediment, preferably of a contrasting type (which would allow the layers to separate when later reexposed). While buried for millions of years, the original sediment lithofies (turns into rock). Finally, the tracks are reexposed in modern times by erosion or other forces. Of course, the tracks also must be found and studied before they are destroyed by weathering, quarry workers, or other dangers. Tracks formed under less ideal conditions tend to be distorted or indistinct, if preserved at all.
    Recent research suggests another mechanism of print formation, which involves a dinosaur walking on a very soft surface. In such a case, the animal's feet may push into firmer layers below the surface. The soupy surface material may then rush back over the upper depressions, simultaneously covering the prints made in the lower layers. The subsurface prints are known as underprints, undertracks, or ghost tracks. Because they are buried as soon as they are made, any erosion or other destructive forces occurring at the surface would pose no threat to them, increasing their chances of being preserved." [Go to this webpage as it relevant to the Purbeck dinosaur footprints.]

    Kullberg , J.C., Oloriz, F., Marques, B., Caetano, P.S. and Rocha, R.B. 2001. Flat-pebble conglomerates; a local marker for Early Jurassic seismicity related to syn-rift tectonics in the Sesimbra area (Lusitanian Basin, Portugal). Sedimentary Geology, 139 49-70. Abstract: Flat-pebble conglomerates have been identified in the Lower Toarcian (Levisoni Zone) carbonates in the Sesimbra region (30 km south of Lisboa, Portugal) and related to submarine mass movements. Their origin is explaiend through a three-stage model based on the comparitive analysis of potential generating mechanisms taking into account timing and type of geodynamic evolution in the Lusitanian Basin: (a) differential lithification of thin carbonate and non-bioturbated horizons embedded within a more argillaceous matrix; (b) disruption by seismic shocks related to active extensional faulting and block tilting; and (c) gravity sliding mixing material resulting from broken lithified horizons. This sequential process originated flat-pebble conglomerates during early Jurassic phases of syn-rift evolution in the southern Lusitanian Basin. End of Abstract. [This paper is not on the Pubeck Formation, but is significant because flat-pebble conglomerates (e.g. the "Pellety Bed") are well known features of the Soft Cockle Member of the Purbeck Group on the Lulworth High. In the shallow-water Purbeck facies, a storm origin rather than a seismic origin is more likely, although liquifaction by Late Kimmerian seismic activity is known in the Purbecks of this area. The paper is useful for comparison and references.]

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    Lacroix, A. 1897. Le gypse de Paris et les mineraux qui l'accompagnent (premiere contribution à la mineralogie du bassin de Paris), Masson et Cie, 1897, 296 p. By Alfred Lacroix. Classic work on the crystallography of the Eocene gypsum of Paris.
    Lake , R.D., Young, B., Wood, C.J. and Mortimore, R.N. 1987. Geology of the Country around Lewes. British Geological Survey Memoir, Sheet 319. 117pp.


    Lake, S.D. 1986. Brecciated pipes in the Broken Beds, Purbeck Limestone Formation. Proceedings of Dorset Natural History and Archaeological Society, 107 (for 1985), 191-192. By S.D. Lake, at the time, Department of Geological Sciences, University of Durham, South Road, Durham.
    Previously unrecorded breccia pipes extend up from the underlying Broken Beds into the undisturbed sedimentary cover. These have been identified at Bacon Hole and Durdle Door in south Dorset. The likely cause for the formation of the Broken Beds is re-evaluated. The results imply both diagenetic and tectonic effects during the Tertiary uplift of the Isle of Wight/Purbeck monocline alonga former Mesozoic roll-over anticline. [end of abstract]

    [some incomplete extracts follow:]

    " ---- Recent fieldwork by the author led to the discovery of breccia pipes that extend, in some cases, at least 10 metres from the Broken Beds into the overlying Lower Purbeck sequence. Therefore these hypotheses listed by West (1960) must somehow explain this phenomena or alternative hypotheses put forward.

    The occurrence of the breccia pipes is particularly well exhibited at Bacon Hole (SY842797) where the largest upstanding stack has a peculiar knoll at the top (Fig. 1). This is particularly well seen in Plate 1 of Arkell's (1947) Memoir. On close examination this knoll displays the typical limestone brecciation associated with the Broken Beds, yet lies at least 5m above the main Broken Beds horizon. Examination from the seaward (southern) side of the stack particularly well displays the upward extension from the main Broken Beds horizon. A small scale example is well displayed on the eastern side of the stack, the brecciation extends some 4m into the overlying "Cypris" Freestone Member (Fig.1). The width of both of these pipes is approximately 4m.

    Durdle Door eastern promontory (SY807803) also displaysa similar feature. The bedding planes of the 'Cypris' Freestones show a hemispherical brecciated body at beach level between the beach and the promontory. This brecciated body bears remarkable similarity to the underying Broken Bed horizon yet lies some distance above it. The location and size of this brecciated body is interpreted as reflecting another breccia pipe and not a separate Broken Bed horizon, such as those identified at Worbarrow Tout by West (1975) and Ensom (1985). Clearly these breccia pipes are important in the evolution of the Broken Beds horizon.
    In the light of this work [previous papers by West] a further contribution can be made resulting from the observed breccia pipes and new structural evidence. The evolution of the Broken Beds can perhaps be envisaged as follows: Primary gypsum was intercolated with calcareous shale and pelletoidal limestones in the lowest portion of the Broken Beds, whilst ostracodal biosparites, intrasparites and pelletoidal limestones occurred towards the top of the Broken Beds unit (West, 1964, 1975). Increasing depth of burial of the unit resulted in dehydration of the gypsum to anhydrite. This undoubtedly occurred prior to the Eocene and the initiation of uplift. The depth of burial was probably less than 1500 m on based on known sedimentary thickness of the overlying units. This structural evidence is also in agreement with theoretical studies which demonstrate that dehydration of gypsum occurs at a temperature of 42 degrees centigrade. Similar consideration of the present day geothermal gradient (30 degrees C / Km) allows a minimal depth estimate of dehydration. Coincident with this increasing burial, calcitisation of the lower Purbeck evaporite sequence took place in response to decarboxylation of organic matter. The dehydration resulted in an approximately 38% volume decrease (Blatt et al., 1972) thus resulting in abnormal fluid pressures. Fluids were undoubtedly derived from the nearby algal limestones and clays. Locally the dirt beds (the Great Dirt Bed in particular) that lie at the base of the Broken Beds sequence may have acted partly as an impermeable layer preventing downward percolation of fluids. This combined with increasing hydrostatic pressure associated with burial may have caused the pressured fluids to have outflow diapirically or resulted in hydrofracturing into the overlying 'Cypris' Freestones Member prior to flexuring.

    [continues with text]

    [See also the Fig 1 - a diagram of a breccia pipe in an offshore Mupe Rock at Bacon Hole.]

    [Reference and - END OF ARTICLE]

    Lake, S.D. 1986. Evidence for Bathonian and Portlandian Synsedimentary Fault Movement in Dorset. Proceedings of the Dorset Natural History and Archaeological Society, vol. 187, pp. 189-190. Changes in thickness of the Bathonian Boueti Bed (base of the Forest Marble) at Herbury (SY612811), Fleet Lagoon, is recorded. The change is from 9cm thick to 28cm thick in a distance of 10m.
    The basal Purbeck section at Durlston Head, described by West (1960), is partly re-interpreted so as to involve penecontemporaneous growth-fauling. The thickening of the basal Purbeck Caps from south to sorth across the F3 fault is so explained. However, south of the F3 fault is a major tectonic downbulge affecting evaporites. The Purbeck Caps involved are largely of replaced anydrite (calcite and celestite replacements). Flowage contortions are actually visible just north of the fault F3. This does not seem a convincing case for growth-faulting because this is an evaporitic sequence. However, growth faulting would not necessarily be unexpected within the Purbeck Group (with its very varying thickness) but not necessarily just here.
    Lamplugh, G.W., Kitchen, F.L. and Pringle, J. 1923. The Concealed Mesozoic Rocks in Kent. Memoirs of the Geological Survey, England and Wales. Publised by Order of the Lords Commissioners of His Majesty's Treasury. Printed under the authority of His Majesty's Stationery Office. 248pp. This includes various short sections on the Pubeck Formation. Example extract (p. 56):
    [Hothfield is in the Weald of southeast England near the margin of the Purbeck Basin, and not far from Folkstone.]
    "This boring was made in 1898-9, on a site just west of Parsonage Farm, a little south of Hothfield Railway Station (3 miles N.W. of Ashford), at about 200 ft. above O.D. We have not examined any material from the boring, but understand that some specimens are preserved in the Museum at Owen's College, Manchester. A brief abstract of the section was published by Prof. W. Boyd Dawkins, and full details of all the beds below the Atherfield Clay, from the MS. of Prof. Dawkins, were included in the Geological Survey Memoir on 'The Water Supply of Kent' (by W. Whitaker, F.R.S.), published in 1908 (p. 225). These details have been condensed and reclassified in the section given below. The boring began near the top of the Folkestone Beds, so that the section gives practically the whole of the Lower Greensand, along with the Wealden and Purbeck formations, and the upper part of the Portlandian." [continues with borehole log. The Cinder Bed seems to be represented - record of grey marlstone with plates of echinoderms, presumably Hemicidaris, and fish vertebrae. - 2 feet, 9 inches. Under it is dark shale with pyrites and green grains, presumably glauconite, and Ostrea, presumably Praeexogyra].

    " As might be expected from its position, the section, so far as it goes, finds its olosest equivalent in that of the Pluckley boring 4 miles distant to S.W., while it can be compared almost equally well with that of the Brabourne boring nearly 7 miles distant to E.S.E. At Pluckley the Wealden-Purbeok series was much thioker, in accordanoe with the general rule as to the S.W. expansion, but a correspondence in many of the details of the two sections oan be readily recognized, so that we have been enabled in the tabular details above to divide this series on the same scheme as that of the Pluckley seotion in the previous memoir. The Hastings Beds at Hothfield have less than half their thickness at Pluckley, and the same proportion holds in respect to the Weald Clay, when allowance is made for the upper part not included in the Pluckley section. The Purbeck Beds are 68 ft. thick at Hothfield, as against 101 ft. at Pluckley; they show a similar sequence of green clays, pale marlstones, etc., with breccia-bands above, and grey and blue flaggy marlstone and shaly clays below; but the gypsiferous beds found at the base at Pluckley and in still thioker development at Penshurst (op. cit., p. 70) appear to be absent at Hothfield, as they also were at Brabourne (op. cit., p. 38). The presence of Ostrea and eohinoderm-fragments in the lower part of the Purbeck series recalls the marine intercalations seen at Penshurst and Brabourne (op. cit., pp. 40, 69, 70, 145, 184). The description of the breccia bands [e.g. - units above the Cinder Bed - "green clay and white breccia; green marl and marlstone with white breccia and pebbles" etc. - some type of sedimentary breccia with rip-up clasts?] probably indicates the persistence of the peculiar rock observed at Brabourne and illustrated by a photographic plate in the previous memoir (op. cit., p. 40). The Portland Beds, so far as proved, show the same general type as at the other three borings mentioned above."
    See also pp. 229-230 - Purbeck Beds - in Faunal Aspects and Correlation of the Strata.
    Lees , G.M. and Cox, P.T.C. 1937. The geological basis of the present search for oil in Great Britain by the D'Arcy Exploration Company Limited. Quarterly Journal of the Geological Society of London, 93, 156-194. [mention of traces of oil in Purbeck strata]
    Leinfelder , R.R. 1987. Formation and significance of black pebbles from the Ota Limestone (Upper Jurassic, Portugal), Facies, 17 (1987), pp. 159-170.
    Lukashevich , E.D., Coram, R.A. and Jarzembowski, E.A. 2001. New true flies (Insecta : Diptera) from the Lower Cretaceous of southern England. Cretaceous Research, 22, 451-460. Abstract: The fossil record of Eoptychopteridae, Ptychopteridae and Dixidae (Insecta; Diptera) is discussed. One new genus and eight new species are described from the English non-marine Lower Cretaceous (Purbeck and Wealden groups): Eoptychoptera longifurcata sp. nov., Eoptychoptera britannica sp. nov., Eoptychopterina demissa sp, nov., Eoptychopterina dimidiata sp. nov., Eoptychopterina camura sp. nov. (Eoptychopteridae), Brodilka mitchelli gen. nov., sp. nov., Zhiganka woolgari sp. nov. (Ptychopteridae) and Eucorethrina westwoodi sp. nov. (Dixidae). Bittacomorphella miocenica (Cockerell, 1910) is transferred to Ptychoptera.
    Lydekker , R. 1889. On certain chelonian remains from the Wealden and Purbeck. Quarterly Journal of the Geological Society, London, 45, 511-518.

    Lydekker, R. and Boulenger, G.A. 1887. Notes on Chelonia from the Purbeck, Wealden and London Clay. Geological Magazine, (3), vol. 4, 270-275.

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    Maillard, G. 1884. Invertebres du Purbeckien du Jura. [Invertebrate Fossils of the Purbeck Strata of the Jura Mountains]. Mem. Soc. Pal. Suisse, vol. 11. 159pp. [Memoirs of the Palaeontological Society of Switzerland, vol. 11.]. By Gustave Maillard, 1860-1891, Swiss-born geologist. In French. Schweizerische palaontologische Abhandlungen. [Abhandlungen der Schweizerischen Palaeontologischen Gesellschaft]. Published by C. Schuchardt, 1884. With a Supplement in 1886, vol. 12.
    Maliva , R.G. and Dickson, J.A.D. 1992. The mechanism of skeletal aragonite neomorphism - evidence from neomorphosed mollusks from the Upper Purbeck Group (Late Jurassic - Early Cretaceous), southern England. Sedimentary Geology, 76, 221-232.
    Abstract: The trace element geochemistry and microtextures of neomorphosed mollusks from the upper Purbeck Group (Late Jurassic-Early Cretaceous) of southern England suggest that calcite replacement of aragonite occurs by a force of crystallization-driven mechanism similar to that of non-polymorphic skeletal carbonate replacement reactions, such as silicification. The Purbeck neomorphic calcites are substantially enriched in Mg, Mn, and Fe, and depleted in Sr compared to skeletal aragonite indicating that the neomorphic reaction zones were not chemically isolated from the bulk pore waters to a significant degree. Neomorphic calcite microtextures are fundamentally similar to the replacement microtextures of silicified and celestite-replaced fossils, in terms of the degree and style of preservation of traces of skeletal microtextures in authigenic crystals and the relationships of authigenic crystal morphology and crystallographic orientation to shell microtexture. The neomorphic replacement of aragonite by calcite differs from most non-polymorphic replacement reactions in that the calcite cannibalizes aragonite. Decreases in the intraskeletal pore water calcium carbonate ion activity product caused by calcite precipitation results in aragonite dissolution adjacent to aragonite-calcite contacts (i.e., chalkification) in some fossils. Chalkification does not occur in non-polymorphic replacements of skeletal carbonate.
    Mansel-Pleydell , J.C. 1888. Fossil Reptiles of Dorset. Proceedings of Dorset Natural History and Antiquarian Field Club, vol. 9. pp. 1-40.

    Mansel-Pleydell, J.C. 1896. On the Footprints of a Dinosaur (Iguanodon?), from the Purbeck Beds of Swanage. Proceedings of Dorset Natural History and Antiquarian Field Club, vol. 17, pp. 115-122.
    Mantell , G.A. 1854. Geological Excursions round the Isle of Wight and along the Adjacent Coast of Dorsetshire; illustrative of the most interesting Geological Phenomena and Organic Remains. 3rd Edition, H.G Bohn, London, xxxi + 356p.
    Marshall , J.D. 1982. Isotopic composition of displacive fibrous calcite veins: reversal in pore-water trends during burial diagenesis. Journal of Sedimentary Petrology, 52, No. 2, 0615-0630. Abstract: Stable isotope and petrographic analyses of diagenetic calcite ("cone-in-cone" and "beef") veins from British Jurassic and Lower Cretaceous shales have been used to determine the environment of precipitation of fibrous calcites. Successive growth took place by antitaxial displacive addition at the vein margins, away from primary sedimentary laminations or early diagenetic conconcretions. Carbon and oxygen isotopic ratios (del 13 C plus or minus 0 and del 18 O -4 to -11 percent) indicate a relatively late diagenetic origin for the veins after tens or probably hundreds of metres of burial, and after cessation of bacterial activity and considerable modification of the oxygen isotopic composition of the pore water. Vein growth was discontinuous and took place in waters of changing isotopic and trace-element composition. Changes are not unidirectional and unlikely to result from the simple evolution of a single connate pore water; reversals in isotopic trends indicate that precipitation took place during periods of renewned (lateral?) groundwater flow, tapping different sources of bicarbonate-bearing solution.
    Martill , D.M. and Naish, D. (Eds.) 2001. Dinosaurs of the Isle of Wight. Palaeontological Association, Field Guides to Fossils: Number 10. The Palaeontological Association, London. 433pp. ISBN 0 901702722. Edited by David M. Martill and Darren Naish, technical editing by David J. Batten, photography by Robert Loveridge and computer generated artwork by Stig Walsh. Price of paperback in 2003 - £16. Contents: Acknowledgements; Preface; 1. Introduction by Martill, D.M., Naish, D. and Hutt, S.; 2. The Geology of the Isle of Wight by Martill, D.M. and Naish, D.; 3. The Global Significance of the Isle of Wight Dinosaurs by Martill, D.M. and Naish, D.; 4. Taphonomy and Preservation by Martill, D. ; 5. Ornithopod Dinosaurs by Naish, D. and Martill, D.M.; 6. Boneheaded and Horned Dinosaurs by Naish, D. and Martill, D.M.; 7. Armoured Dinosaurs: Thyreophorans by Naish, D. and Martill, D.M.; 8. Saurischian Dinosaurs 1: Sauropods by Naish, D. and Martill, D.M.; 9. Saurischian Dinosaurs: Theropods by Naish, D., Hutt, S. and Martill, D.M.; 10. Dinosaur Trace Fossils: Footprints, Coprolites and Gastroliths by Martill, D.M. and Naish, D.; 11. Pterosaurs by Howse, C.B., Milner, A.R. and Martill, D.M.; 12. An Aid to the Easy Identification of the Commoner Wealden Dinosaur Bones by Martill, D.M. and Naish, D.; 13. A Dinosaur Trail by Martill, D.; Glossary of Terms; References, Appendix; Further Reading; Useful Information; Systematic Index. [The book is mostly in monochrome with numerous photographs and diagrams, but there are 16 colour plates in the central part. It contains a mass of information and is exceptionally good value for money. In addition to its main use regarding Wealden strata it is relevant to the Purbeck Group of Dorset, because it discusses the dinosaur contents of a higher part of the Lower Cretaceous in the same general region, and some similar dinosaurs might be expected to have been present in the Purbeck (Berriasian). There is specific reference to Purbeck dinosaurs and Purbeck dinosaur footprints in places, as for example on pages 134 and 135 where Echinodon and Nuthetes are discussed. The chapter on dinosaur footprints, pages 310 et seq. is clearly of significance regarding Purbeck footprints and these are mentioned briefly (particularly of Iguanodon).]
    Martinez-Delclos , X., Nel, A. and Popov, Y.A. 1995. Systematics and functional morphology of Iberonepa romerali n. gen. and sp., Belostomatidae from the Spanish Lower Cretaceous (Insecta, Heteroptera). Journal of Paleontology, 69, (3), 496-508.
    Martini , E. 1972. The genus Eosphaeroma (Isopoda ) in the European Paleogene (in German: Die Gattung Eosphaeroma ( Isopoda ) im eropaischen Alttertiar). Senckenhergiana Lethaea, 53, 65 79.( redescribed two isopod species from the Bembridge Marls of Gurnard Bay, Isle of Wight - lower Oligocene - lagoonal - see Daley papers for palaeoenvironments) (Purbeck isopod analogue)
    Masson, P.H. 1955. An occurrence of gypsum in southwest Texas. Journal of Sedimentary Petrology, vol. 25, No.1, pp. 72-77. By P.H. Masson of the Humble Oil and Refining Company, Houston, Texas. [relevant to Purbeck evaporites, particularly lenticular gypsum.
    Gypsum in the form of crystals and rosettes of selenite has been found in the sursurface clays and sands of the Laguna Madre mudflats of southwest Texas. The habit of the crystals is unusual, and the dominant crystallographic forms are (bar-1 11) and (bar-1 02). The manner in which the crystals grow larger at depth and become lens-like in shape is also of interest. It is concluded that the gypsum precipitates from highly saline sea water which periodically moves in wind-blown sheets across the surface of the mudflats and sinks into the underlying sediment. [This paper is relevant to the topic of the former occurence of lenticular crystals of gypsum in the Purbeck Group of Dorset, England, since mostly replaced by silica, calcite or celestite. See: West (1964).
    Mathewman, R., Cottom, L.J., Martin, Z. and Sephton, M.A. 2012. Organic geochemistry of late Jurassic paleosols (Dirt Beds) of Dorset, UK. Marine and Petroleum Geology, vol. 37, 41-52.
    Paleosols from the lower part of the Purbeck Limestone Group, which crops out extensively in Dorset, southern England, are shown to contain type IV kerogens. Comparisons with Mesozoic organic materials suggest that some of the paleosol kerogen is composed of fossil charcoal. The charcoal would have been produced by wildfires in the undergrowth of Purbeck gymnosperm forests. Contrasting the paleosol charcoal with laboratory produced counterparts suggest that, originally, significant amounts of functionalised organic matter should have persisted. Secondary oxidation and decay processes, therefore, must have removed all but the most resistant aromatic units in the charcoal. The importance of post-fire processes implies a strong influence on preservation from oxygen supply, water washing and host sediment type. These factors may have been related to pedogenesis, relative sea level and local fault movement in the late Jurassic.
    McNamara, K. 2009. Stromatolites: great survival under threat. Geoscientist; the magazine of the Geological Society of London, vol. 19, No. 12, December 2009. Ken McNamara investigates the slime that ruled the Earth for billions of years. Ken McNamara, Department of Earth Sciences, University of Cambridge, UK. [Particularly good photographs, including those of Lake Thetis, which closely resemble Purbeck thrombolitic stromatolites.]
    Melville , R.V. and Freshney, E.C. 1982. British Regional Geology: The Hampshire Basin and Adjoining Areas. Fourth Edition, Institute of Geological Sciences, London, Her Majesty's Stationery Office, 146p. [The standard introductory booklet on the Dorset coast with Purbeck Group.]
    Milne-Edwards , H. 1843. Note sur deux Crustaces fossiles de l'Ordre des Isopodes. (Archaeoniscus Brodiei). Annales de Science Naturelles, ser. 2, vol 20, p. 323. See also Idem 1844, vol 18, p.110
    Milner , A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times.Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268pp. Report from a symposium on the Purbeck Group at the Dorset County Museum, Dorchester, Dorset, March 19-22, 1999. Contains 16 papers and with a preface. Dedicated to the memory of the late Professor Michael House. Price 66 pounds. Published December 2002. With 22 plates, 7 tables and 77 text-figures.

    Milner, A.C. 2002. Theropod dinosaurs of the Purbeck Limestone Group, southern England. Pp. 191-201 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268pp. Abstract: A small, probably juvenile theropod dinosaur, Nuthetes destructor Owen, 1854 from the Berriasian Middle Purbeck Beds, Isle of Purbeck, regarded hitherto as a megalosaur, is redescribed as a dromaeosaur on the basis of distinctive tooth and tooth denticle characters. This represents the first dromaeosaur record from Britain and fills a gap in the stratigraphical occurrence of the family in Europe between the Kimmeridgian in Portugal and the Barremian in Spain. The Purbeck fauna also includes evidence of a large maniraptoran, perhaps a dromaeosaur, although it is not at present possible to determine whether it represents the same taxon as Nuthetes. At least one other theropod taxon is present in the Purbeck Limestone on the basis of isolated teeth which closely resemble those of allosauroids. [By Angela C. Milner, The Natural History Museum, London.]
    Moore , R.C. 1969. Treatise on Invertebrate Paleontology. Part R, Arthropoda 4., vol. 1, 398pp. (Isopods - Purbeck Archaeoniscus).
    Morter , A.A. 1984. Purbeck-Wealden mollusca and their relationship to ostracod biostratigraphy, stratigraphical correlation and palaeoecology in the Weald and adjacent areas. Proceedings of the Geologists' Association, London, vol. 95, pp. 217-234
    Mossop , G.D. and Shearman, D.J . (1973) Origin of secondary gypsum rocks. Transactions of the Institute of Mining and Metallurgy (B), 82, 147-153.
    Mostovski , M.B., Jarzembowski, E.A., Coram, R.A. and Ansorge, J. 2000. Curious snipe-flies (Diptera : Rhagionidae) from the Purbeck of Dorset, the Wealden of the Weald and the Lower Cretaceous of Spain and Transbaikalia. Proceedings of the Geologists' Association, 111, 153-160. Abstract: Four new Lower Cretaceous species of the rhagionid genus Ptiolinites are described: Ptiolinites heidiae sp. nov. and P. raypearcei sp. nov. from southern England, P. almulhae sp. nov. from Spain and P. oudatchinae sp. nov. from northern Transbaikalia. Re-evaluation of the antennal structure allows us to assign Ptiolinites to the subfamily Rhagioninae.
    Mottram, B.H. 1950. Notes on the structure of the Poxwell Pericline, and the Ridgeway Fault at Bincombe Tunnel, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 71, (for 1949), pp. 175-183.

    Mottram, B.H. and House, M.R. 1956. The structure of the northern margin of the Poxwell Pericline. Proceedings of Dorset Natural History and Archaeological Society, vol. 76 (for 1954), pp. 129-135. With a geological cross-section from the Poxwell borehole site (1937) south to Ringstead. This section has been reproduced in House (1993) Fig. 27, p. 95.

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    Needham , J. E. 2011. Forests of the Dinosaurs; Wiltshire's Jurassic Finale.

    Book by John Needham on the Purbeck Fossil Forests of Wiltshire, 2011

    The Hobnob Press, PO Box 1838, East Knoyle, Salisbury, SP3 6FA. By John E. Needham. ISBN 978-1-906978-01-3. 221 pp. Printed by Lighting Source. Paperback, 12 pounds, 95 pence from Amazon (in Jan 2012).

    Introduction and Acknowledgements.
    1. The Purbeck Fossil Forest of Dorset and Wiltshire.
    2. Wiltshire's Plant and Reptile Bed.
    3. The Dorset Connection.
    4. From Wiltshire to the Americas.
    Secrets of Wiltshire's Fossil Forest.
    [This book is full of interesting information on Purbeck fossil trees, their branches, their roots, cones etc, with much new data regarding finds in the Vale of Wardour, Wiltshire. It is very well-illustrated and has a good reference list. In terms of plant material, it provides good links between the unusual, low salinity, basal Purbeck facies of Portesham Quarry, Dorset and the Wiltshire basal Purbeck exposures.]
    Nunn , J.F. 1990. A new tridactyl footprint impression in Durlston Bay, Swanage. Proceedings of the Dorset Natural History Archaeological Society, 111, 133-134.

    Nunn, J.F. 1991. Unpublished Geological Map of Durlston Bay. [see paper below]

    Nunn, J.F. 1992. A geological map of the Purbeck Beds in the northern part of Durlston Bay.Proceedings of the Dorset Natural History and Archaeological Society, 113, 145-148.
    [*** A key paper for the geology of Durlston Bay. Recommended for use with Clements' Log]
    Example extract from the Introduction and Methods:
    Durlston Bay provides the type section of the Purbeck Beds which span the uppermost beds of the Jurassic and the lowest beds of the Cretaceous (AlIen and Wimbledon, 1991). There are many descriptions and measurements of the sequence, starting with Webster (1826) and continuing through Austen (1852) and Bristow (1857). The most complete and accessible vertical section is that of Clements (in Torrens (1969) and the most comprehensive bed-by-bed description is by Clements (1973), with a later vertical section of the middle Purbeck Group by EI-Shahat and West (1983). Interest in this outstanding coastal section shows no signs of diminishing, and Durlston Bay attracts many geological visitors from all over the world. It is unfortunate that, apart from certain prominent marker horizons, it can be difficult for the stranger to relate some of the bed descriptions to the ground. Neither the 1 :2,500 Ordnance Survey, nor the 1 :50,000 Geological Survey (sheet 343) provides the necessary detail to identify beds from the topography. Strahan prepared a geological survey at a scale of approximately 1:10,000 in 1888 and a second edition was released in1902. However, this provides no more detail than Sheet 343. Perhaps most useful of all is the cliff profile of Strahan (1898,92), subsequently modified by Arkell (1947,136) and House (1989,119). However, at a scale of 1:10,000, it is only possible to indicate the approximate position of a few marker horizons. The present objective has been to prepare maps and cliff profiles of the northern part of Durlston Bay at a scale of 1: 1,000 (here reproduced at 1 :2,500) with full integration of the topography and geology (Figures 1 and 2). The intention has been to make it possible for any visitor to the Bay,equipped with the vertical section, to proceed directly to within a few metres of any particular bed. Also it should now be possible to locate field observations to a ten figure map reference (one metre squares).
    Methods: The maps, which were prepared with the permission of the Controller of Her Majesty's Stationery Office, were based primarily on the Trig. Point incorporated in the Coastguard Station (04002 78617), and the bench mark at Craig-y-Don (03441 78201). Five secondary points were then established on the cliff top by triangulation using the above fixed points, together with the Wellington clock tower, the stone pier and Downlands. Heights were determined with a bubble sextant and the secondary points are shown on the maps as spot heights on the cliff top. Secondary triangulation was then used to fix a large number of points at beach level. These positions were then confirmed by stretching a tape measure along the cliff base for almost the full length of the bay. Errors were less than 2 m. In 1987, before the coastal protection works were constructed, the coast was photographed from a small boat at a distance of 150 - 400 m from the shore (depending on the height of the cliff) at low water springs in a flat calm. A 135 mm telephoto lens was used and interlocking sets of 5 - 6 photographs were taken... [continues with excellent maps and cliff section diagrams for Durlston Bay]

    Nunn, J.F. 1993. Unpublished. Lannen Vein, Devils Bed etc. An excavation at low tide just north of the Slipway Fault, Durlston Bay. Graphic log dated 28/9 August 1992 updated 28th June 1993. Details of beef, micrite, biosparite and tenaceous black shale.

    Nunn, J.F. 1994. Unpublished notes on the Lower Purbeck Group, Durlston Bay, 22.12.94. 3 pages. Trenches excavated . Clements' beds 10 to 39..

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    Ogg , J.G., Hasenyager, R.W., Wimbledon, W.A., Channel, J.E.T. and Bralower, T.J. 1991. Magnetostratigraphy of the Jurassic-Cretaceous boundary interval - Tethyan and English faunal realms. Cretaceous Research, 12, 455-482. Abstract: Geomagnetic reversals and magnetic polarity chrons provide an important chronostratigraphic tool for global correlation. An integrated Tithonian-Berriasian biostratigraphic and magnetic polarity time scale for the Tethyan faunal realm for the Tithonian and Berriasian stage is compiled from 17 independent biomagnetostratigraphic sections. This time scale incorporates zones and first/last appearance datums form ammonites, calpionellids, calcareous nannofossils and dinoflagellates. The database provides an estimate of the range of observed appearance datums or zonal boundaries relative to polarity chrons; such apparent "diachoniety" probably results from a combination of preservation of species and paleontological methodology, rather than migration. The lithologic transition from "Rosso Ammonitico" red marly limestone to "Maiolica" white limestone occurs at different times during the Tithonian among the various sections, ranging from polarity zone M22n (mid-Early Tithonian) in some Spanish "slope" and Italian basinal-facies sections, ranging from polarity zone M19n (mid-Late Tithonian) in the central Atlantic and some plateau-facies Italian sections. This widespread lithological change is, therefore, probably a result of shifting local patterns of fertility overprinted on the main regional trend. Magnetostratigraphy from the Purbeck Limestone Formation in the English Boreal faunal realm was obtained from the "classic" section at Durlston Bay in Dorset. The Dorset section displays predominantly normal polarity with a minimum of three reversed-polarity zones, but distortion of the magnetic polarity record by variable rates of sedimentation in this marginal clastic environment coupled with lack of independent correlation methods currently precludes a unique correlation to the Tithonian-Berriasian magnetic polarity time scale. The Tithonian-Berriasian magnetic polarity time scale may eventually provide a global chronostratigraphic definition of the Jurassic-Cretaceous boundary. End of Abstract....[Notes re Purbeck of Dorset: Durlston Bay section. Predominantly normal polarity with three reversed polarity zones but distortion of pattern by variable sedimentation rates coupled with lack of independent methods precludes unique correlation to Tithonian-Berriasian magnetic polarity time scale. M 18r to M 15 r. Keywords: ammonites, Atlantic, Bay, Berriasian, Boreal, calpionellids, chron, correlation, Cretaceous, dinoflagellates, Durlston, geomagnetic, geomagnetism, magnetic, magnetostratigraphy, M-sequence, nannofossils, palaeomagnetism, paleomagnetism, polarity, reversal, Purbeck, stratigraphy, Tithonian, zone]
    Oppe , E.F.
    (Mr. Oppe was a keen collector of fossil footprints in the early 1960s when they were just beginning to obtain publicity in the press. He lived at Worth Matravers and knew the local quarrymen. He drew attention to the unusual non- tridactlyl track in his possession - Purbeckopus pentadactylus and to the trackway discoveries at Suttle's Quarry and elsewhere. At a later stage he assisted the vertebrate palaeontologist Justin Delair and discussed footprints with me when I was at Worth Matravers from time to time.)

    Oppe, E.F. MS scrapbook. Dorset County Museum, Natural History Manuscript Collection, document no. 68. This has not been seen by the webpage author, but is referred to by Ensom (2002) on: Vertebrate trace fossils in the Purbeck Limestone Group of southern England, . It is presumably from about 1960 and may contain more detail in relation to dinosaur footprint records in Oppe and West (1962) below.

    Oppe, E.F. 1965. Isle of Purbeck: Sunny Spaces and Dinosaur Traces. Published by the author, 31pp. A short guide book by Ernest F. Oppe of Peaky, Worth Matravers, Swanage, Dorset. Including historical notes (reprinted) on Corfe Castle by the late Dr G. Dru Drury, F.S.A. Original price - single 2 shillings and 6 pence a copy; and for co-operative spread 10 copies for £1. With a foreword by F. W. Anderson and with an acknowledgement to Justin Delair. [This booklet discusses the Suttle's Quarry dinosaur trackway, Hayward's trackway and others. There are photographs of both Suttle's and Hayward's trackways. Suttle's Quarry was an old quarry reopened on the heights above Herston Cross. The footprints here have been discussed elsewhere (See Charig and other publications) and they indicate a pace of 106cm. There are photographs of both Suttle's and Hayward's trackway. Ten prints in a single line with only small lateral displacement of left and right feet were seen at Hayward's quarry. The pace is referred to as 97 cm., with another figures from separate measurements giving 99 cm. Individual footprints were of about 20 cm length (in the direction of the trackway).


    Oppe, E.F and West, I.M. 1962. The Significance of Fossil Footprints in the Purbeck Beds of Dorset. 4 pp. Old unpublished draft for a short paper that was never submitted, but lists the records to 1962. It was based on a privately circulated manuscript of 1960 by Oppe (Some Latter-Day Fossil Finds in the Isle of Purbeck, Mesozoic Era) which was summarised with additions and modifications by Ian West in 1962 and retained as a type-script, 4pp.
    Abstract : Footprints, mostly ascribed to the Iguanodon, have long been known to occur in the Purbeck Beds. They are significant from a stratigraphic point of view, in indicating very shallow water conditions or subaerial exposure and also the proximity of vegetated land. Several new occurrences are noted and a list of previous records compiled.
    Introduction: Periodically, records of fossil footprints in the Purbeck Beds of Dorset have been published (e.g. Mansel-Pleydell, 1896; Calkin, 1933; Suttle et al., 1962). These are usually tridactyl and ascribed to the Iguanodon but will not be considered here fully from a palaeontological point of view. The frequency of occurrences has been greatly underestimated; not only are many specimens lost in the course of quarrying operations, but others are seen yet remain unrecorded . ... It is particularly unfortunate that there is no record, in that they possess a stratigraphical significance and are an indicator of water depth. It seems unlikely that these footprints could have formed in other than very shallow water or subaerial conditions. Furthermore, the depth of impression, usually 2 and a half (6.4 cm) to 3 inches (7.6 cm), suggests that the beds containing these were partially consolidated, while the attribution of the prints to a large herbivorous dinosaur at least suggests the presence of a vegetated land at no great distance. A lateral facies change to that of a "dirt bed" or fossil soil might well be expected at the appropriate horizon.
    Particular Features of Some Unrecorded Prints: With the exception of a rare five-digit footprint [Oppe's specimen of Purbeckopus pentadactylus - although actually with four toes according to Ensom, 2002], all specimens are tridactly. The length from heel to toe is unreliable, owing to the possible dragging of the feet, but it not greatly different from the width, usually about 12 inches (30 cm) or less. An exceptional width of 18 inches (46 cm) is sometimes found but this track is clearly a larger than the actual foot which made the impression... Purbeck quarrymen often come across footprints and in one case remember the recurrence of a mishapen foot in a particular trackway. In another case a trackway was said to form a complete circle. It is also generally known in the quarries that one footprint shows in two or three superimposed slabs, the displacement of the original partially consolidated bed continuing down for up to 6 inches (15cm) [See Lockley, 1991 on "undertracks"].. Thus one overlying cast, which is usually lost in quarrying, is found above several superimposed imprints each with a corresponding bulge on their lower surfaces.
    Footprint horizons in Dorset. (As known to Mr Oppe in 1960 with some additions by Ian West in 1962):
    Haywards Quarry, No. 7, Spyways, Langton Matravers - Roach - three prints of 9 inches and two smaller. All point west;
    Locks Quarry, Acton, Langton Matravers - Roach (Pink Bed) - two prints 11 inches apart, 18 inches but probably the lowest slab of a superimposed series, in Mr Oppe's collection;
    Cobbs Quarry, Acton, Langton Matravers - Roach - two prints each 9 inches, about 9 inches apart;
    Cobbs Quarry - Roach - medium sized, at Worth Matravers.
    Cobbs Quarry - Roach - 18 inch cast in the County Museum, Dorchester;
    Swanage area, exact location unknown - Laning Vein - preserved at Swanage, medium size, one natural cast; Langton Matravers area, exact location unknown - bed unknown - good prints supplied to collectors in Southall and Brighton.
    Landers Quarry, Gallows Gore, Langton Matravers - Roach - five prints preserved at Corfe Castle, 8 to 12 inches;
    Unknown locality - preserved at Worth Matravers; Unknown locality - preserved at Worth Matravers;
    Langton Matravers area - bed unknown - 8 inches, preserved at Bristol;
    Langton area - bed unknown - on display in the shop window of the Purbeck Press, Swanage;
    Swanage - Corbula Beds - Mansel-Pleydell, 1896 p. 115 et seq., print and cast (natural) with "fucoidal" marking [trace-fossils - burrows - may be Thalassinoides];
    Peveril Point, Swanage, bottom of rugged path to the beach - Unio Bed of the Upper Purbeck - Ord, 1914, p. 342 - "distinct footprints of a large Iguanodon which are rapidly being worn away by modern feet, and unfortunately the slab is too large for removal."
    Suttle's Quarry, Herston, Swanage - Roach (Pink Bed) - Anonymous (1962), Suttle et al. (1962), Charig and Newman (1962), Swaine etc. - At least 25 feet (7.6 m) of uninterupted trackways consisting of two parallel rows of prints two feet (61 cm) apart. Width of individual prints 1 foot (30 cm), length of "stride" 2 feet (60 cm) [unreliable? Is this actually the pace or step not the full stride with the same foot?], trackway heads in the direction 240 degrees (to the southwest). Another single trackway mentioned by Swaine (1962) is present.
    Locality unknown - Roach, above and also in Pink Bed - Calkin (1933), 14 prints in two trackways like those of Suttle's Quarry. Prints 11 inches (28 cm) wide.
    Swanage or Langton Matravers area, exact location unknown - Roach Bed - Benfield (1948, p. 32), 3 footprints found by Jimmy Chinchin and his brother, in an underground mine, purchased by a museum for 20 pounds.
    Conclusions: Tridactyl footprints have frequently been discovered in the Middle and Upper Purbeck Bed, especially in the much-quarried Roach. At least three of the above-listed occurrences are however from the Durlston Bay cliff section, and it is clear that the stratigraphical distribution is not entirely controlled by the presence of well-exposed surfaces at the quarried horizons... Thus, in spite of numerous exposures and a vast degree of quarrying on Portland, the absence of well-authenticated tridactyl footprints in the Lower Purbeck Beds of Dorset requires explanationMansel-Pleydell (1862, p. 122) records, though, that he had been told by a Mr. Hardy that footprints had been seen in these beds. Although it is possible that examples might be found at suitable horizons in the future [we are now in the future, in the 21st century, and they have been found, and indeed only at certain horizons. See webpage on Dinosaur Footprints on Portland. ], there is a general absence in spite of mudcracks indicating suitable conditions for their preservation. Probably the highly saline and rather arid environment that persisted through most of the Lower Purbeck Beds, commencing in the Caps ( (West, 1961) was unfavourable to large dinosaurs [note those footprints since found on Portland are small]. The general absence of dinosaur bones in these also tends to confirm this view.
    References: Anonymous (1962); Benfield (1948); Calkin (1933), Mansel-Pleydell (1896), Ord (1914), Suttle, Brown, Oppe and White (1962), Swaine (1962), West (1961). [References are not given in full here because they are listed in this bibiography. These notes were written more than 40 years ago and since then many more finds have been made. For more information see Ensom (2002) on: Vertebrate trace fossils in the Purbeck Limestone Group of southern England, , and particularly his "Bibliography of vertebrate tracks from the Purbeck Limestone Group of Dorset," pp. 217-220. ]

    Oertli , H.J. 1963. Ostracodes du "Purbeckien" du Bassin Parisien. Revue de L'Institut Francais du Petrole , 18, No. 1, January, 1963. Paris. Abstract: The analysis of cuttings from some 12 oil drillings in the Aisne department (between Reims and Paris) lead to identification of some 20 species of Ostracoda (of which I new subspecies and several unknown forms) which all belong to the lower Purbeckian stage (English classification). The middle and upper Purbeckian stages do not seem to be present and the Valanginian-Wealdian stage, if it is represented, has left no trace of microfauna. Deposits between the Purbeckian and middle Kimmeridgian (after Arkell) are present under lagoonal facies (several local zones are suggested); this accounts for the fact that these stages also are commonly named "Purbeckian" in petroleum geology. [With 7 plates containing good photographs of ostracods. 57 species are shown, including Cypridea dunkeri Jones, for example. This is well-known from the (relatively unusual) Lower Purbeck freshwater facies of Swindon and Portesham in England. It is typical of the lower part of the Lower Purbeck. Also "Cypris" purbeckensis etc. Fig. 6 is a correlation chart relating the French borehole "Purbeckien" to Upper Kimmeridgian to Lower Purbeck of Dorset, and to the Eimbechauser Schichten, the Munder Mergel and the Serpulite of northwest Germany.]
    Owen , R. 1853-89. Fossil Reptilia of the Wealden and Purbeck Groups. Monograph of the Palaeontographical Society, London.

    Owen, R. 1854. On some fossil reptilian and mammalian remains from the Purbecks. Quarterly Journal of the Geological Society, London, 10, 420-433.

    Owen, R. 1855. Notice of some new reptilian fossils from the Purbeck Beds near Swanage. Quarterly Journal of the Geological Society, London, 11, 123.

    Owen, R. 1861. Palaeontology or A Systematic Summary of Extinct Animals and Their Geological Relations. 2nd Edition, Adam and Charles Black, Edinburgh, 463pp.

    Owen, R. 1871. Fossil Mammalia of the Mesozoic Formations. Monograph of the Palaeontographical Society, 33, 1-115.

    Owen, R. 1874-89. Reptilia of the Mesozoic Formations. Monograph of the Palaeontographical Society, London.

    Owen, R. 1879. On the association of dwarf crocodiles (Nannosuchus and Theriosuchus pusillus e.g.) with the diminutive mammals of the Purbeck shales. Quarterly Journal of the Geological Society, London, 35, 148-155.

    Owen, R. 1884. History of British Fossil Reptiles. Cassel. London.

    Owen, R. 1894. The Life of Richard Owen.

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    Patterson, C. 1966. British Wealden Sharks. Bulletin of the British Museum (Natural History), 11, 281-350.
    Pearce , C.R., Hesselbo, S.P. and Coe, A.L. 2005. The mid-Oxfordian (Late Jurassic) positive carbon-isotope excursion recognised from fossil wood in the British Isles. Palaeogeography, Palaeoclimatology, Palaeoecology, 221, Issues 3-4, 343-357. By Christopher R. Pearce, , Stephen P. Hesselbo, and Angela L. Coe. Abstract: The carbon-isotope ratios of fossil wood have recently been confirmed as a proxy for changes in the isotopic composition of palaeoatmospheres. Carbon-isotope data from fossil wood samples collected from the Jurassic (Oxfordian) Staffin Shale Formation on the Isle-of-Skye, Scotland (Boreal/Sub-Boreal ammonite zonation) reveal a long-term positive carbon-isotope excursion of at least 3 permil. This excursion reaches a maximum in the mid-Oxfordian, and closely matches the carbon-isotope ratios previously reported from belemnites collected from the same section and carbon-isotope data from carbonates in other European sections. This confirms that the mid-Oxfordian positive carbon-isotope excursion affected the total exchangeable carbon reservoir. Fossilised wood samples collected at a higher stratigraphic resolution, but over a shorter interval from the Corallian Group in Dorset, England (antecedens, parandieri and cautisnigrae subzones; NW European ammonite zonation) show considerable scatter in their carbon-isotope ratios, and no trends are discernable. The combined Isle-of-Skye and Dorset dataset shows that the long-term Oxfordian positive carbon-isotope trend coincides with a long-term relative sea-level change, and that the most positive carbon-isotope ratios occur across the plicatilis–transversarium biozonal boundary (Sub-Mediterranean ammonite zonation). This implies that the carbon-isotope excursion was not caused by the well-documented rise in sea-level in the transversarium Zone. Although very low carbon-isotope ratios from fossil wood samples are recorded from the Nodular Rubble Member (parandieri Subzone) of Dorset, there is not a sufficiently coherent signal to ascribe these values to the gas–hydrate dissociation event previously hypothesized from the carbon-isotope ratios of Tethyan marine carbonates. A microscopal analysis of the charcoalified debris from the Staffin Shale Formation indicates a prevalence of the wood genus Cupressinoxylon [the Purbeck fossil tree, described in the papers of Jane Francis], derived from a cheirolepidiaceaen conifer. .

    Perry , C.T. 1994. Fresh-water tufa stromatolites in the basal Purbeck Group (Upper Jurassic), Isle-of-Portland, Dorset. Geological Journal, 29, 119-135. Abstract: Recent interpretations of the tufaceous limestones from within the 'Caps Beds' on the Isle of Portland have suggested a depositional environment of intertidal flats and lagoons with typically higher than normal marine salinity levels, a stark contrast with earlier ideas of a freshwater origin. However, evidence is presented in this paper to show that these deposits are indeed most likely to be freshwater in origin. The micro-fabrics observed are typical of those seen in freshwater tufas forming at the present day, and contrast with those observed within intertidal/subtidal stromatolites. Furthermore, the Portland deposits lack syndepositional evaporite deposits, they lack recognizable intertidal deposits, and any lagoonal sediments observed are depositionally distinct from the tufas. Finally, the soil horizons observed are clear evidence of periodic subaerial exposure and isolation from marine influences. Four facies types are identified on Portland: (1) tufaceous limestone; (2) littoral grainstones; (3) subaerial stromatolites; and (4) paleosols. Each facies is repeated a number of times through the sequence, and evidence is presented to show that these formed in a marginal marine setting as a response to a series of minor transgressive (soils to freshwater lakes/lagoon to saline marine/lagoonal) and regressive events (saline marine/lagoonal to soils). The tufa stromatolite deposits themselves, which are often developed around cylindrical holes (representing former tree trunks and branches), are shown to have developed seasonally, by the precipitation of carbonate, due to microbial activity within the freshwater lake environment. Precipitation appears to have been most intense around tree bases (and any associated vegetation), where an active biofilm developed on the underlying soil substrate. Two distinct textures are recognized in this material: (1) micro-porous and (2) macro-porous. These developed together in a crudely laminated, semi-concentric pattern around the holes and together may represent a seasons growth of tufa.
    [This paper is particularly useful in providing detailed description and showing the unusual features of the Purbeck stromatolites. The present writer considers that the lack of a freshwater gastropod fauna, lack of low salinity ostracods, and the presence of pseudomorphs after gypsum in the equivalent strata (the Hard Cap) with stromatolites at the Fossil Forest is evidence against a freshwater origin. See West (1975) for details of high salinity evidence. ]

    Perry, L.L. and Anderson, E.J. 2001. Variations in the cyclic structure of a 4th order sequence across a basin margin: Purbeck Group, Lower Cretaceous, Dorset, England. Abstracts, Geological Society of America, N.E. Section Meeting, vol. 33.


    Petrash, D.A., Gingras, M.K., Lalonde, S.V., Orange,F., Pecoits, E. and Konhauser, K.O. 2012. Dynamic controls on accretion and lithification of modern gypsum-dominated thrombolites, Los Roques, Venezuela. Sedimentary Geology, vol. 245-246, 1st March 2012, pp. 29-47. By: Daniel A. Petrasha, Murray K. Gingrasa, Stefan V. Lalondeb, Francois Orangea, Ernesto Pecoitsa and Kurt O. Konhausera. Petrasha at Department of Earth and Atmospheric, University of Alberta, Edmonton, Alberta, Canada T6G 2E3. Other authors at: Laboratoire Domaines Oceaniques, Institut Universitaire Europeen de la Mer, Universite de Bretagne Occidentale, Place Nicholas Copernic, Technopole Brest-Iroise, 29280 Plouzane, France (Received 29 May 2011. Revised 7 December 2011. Accepted 7 December 2011. Available online 16 December 2011. Editor: B. Jones.)
    Meter-sized thrombolites coated by well developed zonally differentiated microbial mats have been found growing in the shallow waters (depth < 1 m) of a restricted hypersaline lagoon [Laguna Pirata] on the Archipelago Los Roques in Venezuela.
    [Additional clarifying notes from Petrash (2010). This lagoon has hypersaline water characterised by temperatures in excess of 30 degree C, and high total alkalinity and Mg/Ca ratio. In the organic mud and gypsum-dominated basin, the environmental conditions promote bacterial growth and abundant production of EPS (exopolysaccharides) that serve as a reactive organic matrix for precipitation of authigenic carbonates. The microbialites from Laguna Pirata have a crudely laminated to clotted internal fabric and thus can be morphologically regarded as thrombolites. Gypsum crystals comprise the largest part of the microbialites and are partially replaced by aragonite, to form aragonite pseudomorphs after gypsum. These crystals are cemented by microcrystalline calcium carbonate containing up to 25 mol percent Mg, the carbonate cements occurred within an organic matrix, these cements also exhibited specific enrichment trends with depth.]
    By contrast, within the deeper parts of the studied lagoon, sedimentation is characterized by several decimeters of organic-rich material containing gypsum granules lacking carbonate cementation. The lithification of the thrombolites is thought to have proceeded as follows. First, extracellular polymeric substances (EPS) comprising the microbial mat concentrate Ca2 + and other metal cations by adsorption from the hypersaline waters. Second, some of these bound metals then serve as nucleation sites for primary calcium carbonate (CaCO3) precipitation. Third, while carbonate phases are forming in some zones of the mat, in others zones they are being re-dissolved due to the acidity generated through the metabolism of sulfide-oxidizing bacteria, Fourth, as the dissolved sulfide is oxidized into sulfate, the pore-water become saturated with respect to gypsum (CaSO4.2H2O). Fifth, as primary gypsum precipitates within the structures, endolithic sulfate-reducing bacteria metabolize the sulfate moiety in the mineral phase, while simultaneously oxidizing the EPS trapped during accretion. Sixth, as microbial EPS degradation proceeds, the anaerobic oxidation of specific protein fractions of the EPS matrix leads to increased alkalinity, the partial dissolution of gypsum, supersaturation with respect to calcium carbonate, and ultimately pseudomorphic aragonite replacement; this differs from secondary calcite cements in being enriched in 12C, and depleted in minor and trace metals initially associated with the EPS. The biogeochemical processes occurring in this thrombolite-constructing lagoon represent a novel field site for studying the chemical and isotopic processes characterizing early diagenetic gypsum and the role microbes play in its precipitation, dissolution and calcification. In this regard, insights gained from this modern field site will help to better understand mechanisms by which some Precambrian microbialites were lithified.

    Highlights of the paper:

    1. Unusual subaqueous gypsum-rich microbialites [cf. the late Jurassic Purbeck, Dorset thrombolites with abundant pseudomorphs of calcite after lenticular gypsum.]
    2. Gypsum precipitates a result of ongoing bacterial sulphide oxidation.
    3. Gypsum is replaced by pseudomorphic aragonite via sulphate reduction [in the case of the Purbecks has aragonite been replaced calcite within pseudomorphs or was the diagenesis different so that calcite directly replaced gypsum, as would seem to be the case?].
    4. Early diagenetic magnesian calcite cements stabilise the thrombolite framework. [the basal Purbecks seem not to be Mg - rich, although the Soft Cockle Member has evaporites, dolomites and palygorskite.]
    5. There are plausible analogues to ancient metre-scale gypsum microbialites. [The Purbeck thrombolites are an example, although the paper is concerned with Precambrian microbialites.]

    [This is a key paper regarding Purbeck thrombolites.]


    Petrash, D.A. 2010. Metal enrichment in microbial carbonates: the role of carboxylated biomacromolecules. By Daniel Alejandro Petrash. A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfilment of the requirements for the degree of Master of Sciences. Department of Earth and Atmospheric Sciences. Daniel A Petrash, Edmonton, Alberta.

    Philippe, M. and Bamford, M.K. 2008. A key to morphogenera used for Mesozoic conifer-like woods. By Marc Philippe (France),and Marion K. Bamford (South Africa). Review of Palaeobotany and Palynology, vol. 148, Issues 2- 4, January 2008, pp. 184-207.
    There are many problems encountered in the literature in fossil wood taxonomy and nomenclature because the early descriptions and typifications do not match up to the rigors of modern methods and the much larger database that we now have. Redescriptions of specimens and misinterpretation of diagnoses have compounded the problems. In an attempt to correct these problems, we have reviewed the literature for the Mesozoic conifer woods, checked type material wherever possible and listed the most up to date and correct generic names (according to the IBCN). To make wood taxonomy easier to apply we have provided some clarity on terminology not covered by the IAWA Committee [IAWA Committee, 2004. IAWA list of microscopic features for softwood identification. IAWA J. 25, 1-70.] and produced a key for identification.
    Article Outline
    1. Introduction
    2. Methodology
    2.1. Time interval considered
    2.2. Taxonomic principles
    2.3. Procedure
    3. Key for Mesozoic homoxylous pycnoxylic woods
    3.1. Group A (terminal wall of ray cells pitted to nodular)
    3.2. Group B (araucarian or xenoxylean radial pitting)
    3.3. Group C (abietinean radial pitting)
    3.4. Group D (mixed type of radial pitting)
    4. Conclusions
    Appendix A. A list of generic names used for Mesozoic pycnoxylic tracheidoxyls, with some nomenclatural and taxonomical notes
    Appendix B. Original diagnoses of the genera included in the key.

    [The significance to the Purbeck Group is in relation to the silificied wood - Protocupressinoxylon purbeckensis - of the basal Purbeck of the Isle of Portland and the Fossil Forest as described by Francis (1983). See the extract which follows:

    Protocupressinoxylon Eckhold (Eckhold, 1923: 491)- a nomenclatural synonym of Protobrachyoxylon Holden, 1913 (Philippe, 1993), but not of Paracupressinoxylon Holden ex Torrey (the mention of both syntypes of Paracupressinoxylon being included by Eckhold is an error of Vogellehner (1968: 152)). The name Protocupressinoxylon is illegitimate, and the circumscription of its legitimate nomenclatural synonym (Protobrachyoxylon) is doubtful (see this entry above). In xylological literature Protocupressinoxylon is used by most authors as the name of a morphogenus including woods with mixed type of radial pitting and cupressoid oculipores. Most if not all the Protocupressinoxyla described to date clearly have cupressoid oculipores, but arranged in araucarioid cross-fields, which is not in contradiction with Eckhold's diagnosis but which puts them close to Brachyoxylon Hollick et Jeffrey (Philippe, 2002). In the literature there is a great amount of confusion because although some authors give a clear definition for "cupressoid oculipore", none to our knowledge have drawn a clear line between "cupressoid cross-fields" and "araucarioid cross-fields" (see however IAWA, 2004). In our opinion all the ambiguity about the use of Protocupressinoxylon originates here. In 1995 Philippe made two proposals, firstly to consider "araucarioid" a cross-field with numerous oculipores (either cupressoid or taxodioid) which alternate and which are contiguous (note that the areola of these semi-areolate pits is frequently faint or even not preserved in fossil wood); and secondly that "cupressoid cross-fields" be considered as a cross-field with few (usually no more than four) cupressoid oculipores, widely spaced and usually ordered in horizontal lines or columns. However, the earlywood of modern Araucariaceae very rarely has the cupressoid type of cross-field, whereas modern Cupressaceae s.l. very rarely have exclusively araucarioid cross-fields in the earlywood (but again this is not intrinsically relevant to building a parataxonomy). Amongst Mesozoic wood species already described we cannot identify a clear and unambiguous candidate for a neotype for Protocupressinoxylon. Should such be identified, we think a proposal for the conservation of that genus ought to be put forward.]

    Philippe , M., Barbacka, M., Gradinaru, E., Iamandei, E., Iamandei, S., Kazmer, M., Popa, M., Szakmany, G., Tchoumatchenco, P. and Zaton, M. 2006. Fossil wood and Mid-Eastern Europe terrestrial palaeobiogeography during the Jurassic-Early Cretaceous interval. Review of Palaeobotany and Palynology, 142, Issues 1-2, November 2006, pp. 15-32.
    Abstract: Palaeobiogeography plays an important role in the evolution of continental plants. This has been demonstrated mainly for modern biota and for past biota on a very large scale only. During the Jurassic - Early Cretaceous Mid-Eastern Europe was an archipelago, thus a particularly suitable area for a more detailed study. We investigated the area's plant palaeobiogeography, using fossil wood, with information from both a literature survey and investigation of new samples. There is a clear north-south differentiation of wood floras. The northern part of the archipelago, which was connected by a shallow sea, has a homogenous flora. A small terrane in the south, separated by true oceanic crust, seems to have had a peculiar flora, lacking widely distributed elements but displaying an endemic taxon with Gondwanan affinities. Compared to Western Europe, Mid-Eastern Europe has a Jurassic-Early Cretaceous wood flora with similar diversity, except for the Late Jurassic, when it was limited to a single taxon, the widespread Agathoxylon Hartig. The wood flora of northern Gondwana is less diverse across the time interval under consideration, except for the Late Jurassic again. Taphonomic bias cannot be ruled out, but this low diversity during the Late Jurassic suggests stressful climatic conditions for Mid-Eastern Europe.

    Philippe , M., Billon-Bruyat, J-P., Garcia-Ramos, J.C., Bocat, L., Gomez, B. and Pinuela, L. 2010. New occurrences of the wood Protocupressinoxylon purbeckensis Francis: implications for terrestrial biomes in southwestern Europe at the Jurassic/Cretaceous boundary. Palaeontology, vol. 53, Pt. 1, 2010, pp. 201-214.
    Previously known from the Kimmeridgian-Portlandian of Dorset (UK) only, Protocupressinoxylon purbeckensis wood is reported here from the Kimmeridgian of Asturias (Spain) and Ajoie (Switzerland). The morphospecies taxonomy and nomenclature are discussed, and new supplementary illustrations are given. The P. purbeckensis tree was growing in dry strongly seasonal (tropophilous) environments, and the new occurrences suggest that such a climate prevailed on land all over southwestern Europe at the end of the Jurassic (Kimmeridgian sensu anglico - Portlandian). The review of fossil wood data indicates that such a stressful environment may have constrained terrestrial biocoenoses and their evolution at the Jurassic - Cretaceous boundary. But wood generic diversity curves are also strikingly similar to that drawn 20 years ago for nonmarine tetrapods, implying a fossil Lagerstatte effect.
    With regard to taxonomy of Protocupressinoxylon see the following, on p.208 of Philippe et al. (2010), a useful and clear explanation of the situation in 2010:
    "There is a nomenclatural problem with Protocupressinoxylon Eckhold. This morphogenus is a junior nomenclatural synonym of Protobrachyoxlon Holden (Philippe 1993) (but not of Paracupressinoxylon Holden; Philippe and Bamford 2008). Thus, and despite that Protocupressinoxylon was frequently used, it is illegitimate. Conservation has never been proposed for this genus. Several problems have prevented the proposal for such a conservation. First, all material for Protobrachyoxylon eboracense Holden, the type species of the genus Protobrachyoxylon has been lost (Philippe 2002). Second, from the elements given in P. eboracense protologue, genus Protobrachoxylon is very probably a taxonomic synonym of Brachyoxylon Hollick and Jeffrey, and thus genera Protobrachyoxylon and Brachyoxylon are very probably taxonomical synonyms. Thirdly, Protocupressinoxylon has been used in very different ways, depending on whether authors paid more attention to one or another of the Eckhold's syntypes or Eckhold's diagnosis which unfortunately does not describe oculipore arrangement in cross fields. Fourth, the genus Protopodocarpoxylon was often used for material with araucaroid cross-fields and mixed type of radial pitting (just as in Brachyoxylon Hollick and Jeffrey), in line with the conditions observed by the type material for Cedroxylon blevillense Lignier, one of the Protopodocarpoxylon Eckhold syntypes (Lauverjat and Pons 1978).
    A nomenclatural and taxonomic reappraisal of Mesozoic wood genera is currently in progress by one of us [i.e. one of: Philippe, Billon Bruyat, Garcia-Ramos, Bocat, Gomez or Pinuela]. Meanwhile we [i.e. Philippe et al. (2010)] will use herein the name Protocupressinoxylon purbeckensis Francis, which is well-known and based on well-described material."

    Phillips W.J. 1964. The structures in the Jurassic and Cretaceous rocks on the Dorset coast between White Nothe and Mupe Bay. Proceedings of the Geologists' Association, London, 75, (4), 373-405. By W.J. Phillips, Department of Geology, University College of Wales, Aberystwyth. Abstract: The structures associated with the steep, northward inclined Portland and Purbeck Beds, and the nearly vertical or overturned Wealden Beds and Chalk, exposed on the Dorset coast between White Nothe and Mupe Bay, form the subject of an important paper by W. J. Arkell (1938). Arkell thought that the structures occurred on the steep north limb of a major monocline which was formed by lateral pressures from the south. In the present paper the minor structures in the Purbeck Beds are described in detail and it is shown that they can be related to the development of a fold formed by the increasing northward dip of the underlying massive Portland Beds. The direction of overturning of the minor folds indicates movement of the beds down the dip slope and not upward drag as postulated by Arkell. The formation of the sets of shear planes and faults recognised by Arkell in the Chalk is considered, and it is suggested that they can be divided into two genetic groups. The first group of structures formed during the closing of the syncline, while the second group brought about its modification by thrust displacements on southward inclined thrust planes and late faults. Arkell's conclusions concerning the causes of the reduction in the thickness of the incompetent Wealden Beds are summarised briefly, but by the construction of cross-sections of the main structure, it is demonstrated that the missing portions of the Purbeck and Wealden successions could have been displaced only by thrust movements on southward inclined major faults. A stage-by-stage synthesis of the development of the structures is presented and it is suggested that they were formed as the result of the accommodation of the blanket of largely unconsolidated sedimentary beds above a major thrust fault in the basement. At first a broad flexure developed and this became most pronounced in the highest division, the Chalk, because of the buckling and northward sliding of these beds off the rising land to the south. As the magnitude of the fault increased, successively higher beds fractured and eventually the fault extended to the surface and brought about the displacement and modification of the structures formed during the earlier phase of folding.
    Platt , N.H. 1989. Lacustrine carbonates and pedogenesis: sedimentology and origin of palustrine deposits from the Early Cretaceous Rupelo Formation, W. Cameros Basin, N. Spain. Sedimentology, 36, 665-658.
    Ponomarenko, A.G., Coram, R.A. and Jarzembowski, E.A. 2000. Fossil beetles (Insecta Coleoptera) from the Purbeck Limestone Group of Dorset - a preliminary report. Proceedings of the Dorset Natural History and Archaeological Society, vol. 121 (for 1999). pp. 107-112.

    Ponomarenko , A.G., Coram, R.A. and Jarzembowski, E.A. 2005. New beetles (Insecta: Coleoptera) from the Berriasian Purbeck Limestone Group, Dorset, UK. Cretaceous Research, 26, (2) , April 2005, 277-281. By Alexandr G. Ponomarenko, Robert A. Coramb, and Edmund A. Jarzembowskic. Addresses: a. Paleontological Institute, Russian Academy of Sciences, 123 Profsoyuznaya Str., Moscow 117647, Russia; b. 6 Battlemead, Swanage, Dorset BH19 1PH, UK.; c. School of Human and Environmental Sciences, The University, Reading RG6 2AB, UK and Maidstone Museum and Bentlif Art Gallery, St Faith's St, Maidstone, Kent ME14 1LH, UK. Abstract: Four new beetle species are described from the Lower Cretaceous Purbeck Limestone Group of southern England: Mesogyrus anglicus sp. nov. (Gyrinidae), Coptoclavella purbeckensis sp. nov. (Coptoclavidae), Palaeodytes incompleta sp. nov. (Dytiscidae) and Cretorabus sulcatus sp. nov. (Carabidae). The first three taxa were aquatic; the last is terrestrial but may have frequented the margins of water bodies.
    [end of abstract] "1. Introduction.
    The basal Cretaceous Purbeck Limestone Group consists predominantly of lagoonal sediments best exposed in eastern Dorset, UK. Fossil insects occur in many beds, usually in fragmentary condition. Beetles are numerically the most abundant Purbeck insect order, being represented by several thousand specimens, the majority isolated elytra. Westwood (1854) described numerous taxa, most of which would benefit from re-examination. A single new genus has been described since (Gratshev et al., 1998) , and several families figured without formal description by Coram et al. (1995) and Ponomarenko et al. (2000). This paper describes four new species belonging to the extant suborder Adephaga in the families Gyrinidae, Coptocavidae, Dytiscidae and Carabidae, all collected from the Purbeck type section in Durlston Bay (National Grid Reference SZ 035773 - SZ 040786).
    2. Palaeoecology
    The Gyrinidae, Dytiscidae and Coptoclavidae are predatory aquatic families, the first two still being extant. Their fossil remains in the Purbeck occur in brackish water deposits containing other aquatic insects including Heteroptera, Diptera and Trichoptera (Coram and Jarzembowski, 2002). The rarity and incompleteness of the gyrinid and dytiscid remains suggest that they were transported from other (probably fresher) habitats. The more completely preserved coptoclavids may have lived as adults in the depositional water body, although the absence of fossilised pre-imaginal stages suggests that they did not breed there, this situation is seen in other mid-Mesozoic lagoonal deposits, for example the Tithonian Solnhofen Limestone of Germany (Ponomarenko, 1985).
    Extant carabids are terrestrial predators. Although relatively common as fossils in the Purbeck, their remains, in common with most other terrestrial insects are almost always completely disarticulated, probably because the Purbeck depositional sites were usually some distance (several kilometres) from well-vegetated insect habitat (Coram, 2003). Some Recent carabids, however, frequent shorelines and the rare more complete Purbeck carabid remains may represent individuals that lived on the wide and comparitively barren beaches and flats around the Purbeck water bodies.
    3. Systematic Palaeontology"
    [Systematic palaeontology continues for about four pages and is not reproduced here. See the original publication.]

    Popov , Y. A., Coram, R. and Jarzembowski, E.A. 1999 (for 1998). Fossil heteropteran bugs from the Purbeck Limestone Group of Dorset. Proceedings of the Dorset Natural History and Archaeological Society, 120, 73-76. Summary: Our current knowledge of the first fossil heteropteran bugs of the basal Cretaceous Purbeck Limestone Group is summarised and several taxa figured for the first time. The fauna is compared with others of similar age worldwide. End of Summary. - Notes: These are mostly aquatic or semi-aquatic bugs with piercing and sucking mouth-parts. Giant water bugs of the extant predatory family Belostomatidae are known from the Middle Purbecks of Durlston Bay. Aquatic bugs do not occur in some parts of the Soft Cockle Member because of unfavourable hypersaline conditions, and here fragments of terrestrial forms predominate.
    Pratt , B.R., James, N.P. and Cowan, C.A. 1992. Peritidal carbonates. In: R.G. Walker and N.P. James, Editors, Facies Models and Response to Sea Level Change, Geological Association of Canada, St. Johns, Newfoundland (1992), pp. 303-322.
    Price , G.D. and Mutterlose, J. 2004. Isotopic signals from late Jurassic-early Cretaceous (Volgian-Valanginian) sub-Arctic belemnites, Yatria River, Western Siberia. Journal of the Geological Society, London, vol. 161, no. 6, pp. 959-968. Abstract: This contribution presents the first detailed oxygen and carbon isotope record from the latest Jurassic-early Cretaceous interval of the Yatria River, subpolar Urals, Siberia. Isotopic compositions have been determined on well-preserved belemnite samples from the genera Lagonibelus, Cylindroteuthis and Acroteuthis. These new data indicate a shift to lower temperatures from the late Volgian into the late Valanginian, with some warmer phases recognized within the Ryazanian and earliest Valanginian. The lowest temperatures of the late Valanginian, consistent with subfreezing polar temperatures, are coincident with an inferred eustatic sea-level fall. A late Valanginian positive shift in carbon isotopes correlates with the carbon isotope excursion recorded from Tethyan successions. The most positive carbon isotope values correspond to the most positive oxygen isotope values (and hence lowest palaeotemperatures). In the absence of widespread Valanginian organic-rich black shale deposition, the carbon isotope excursion may point to increased storage of organic carbon in coastal areas and/or enhanced preservation within stratified waters in high-latitude basins. At these higher latitudes, where rates of weathering were presumably much lower because of the prevalent cold climate, the isotopic data may point to pulses of productivity being brought about by increased riverine nutrient transfer and also by nutrients being released by the melting of ice. The correlation between positive carbon isotopes and cool climates may indicate the effectiveness of these high-latitude carbon sinks and their ability to draw down atmospheric CO2, resulting in an 'inverse greenhouse' effect. [Not specifically on the Purbeck, but relevant to Purbeck palaeoclimatology. The Purbeck Group crosses the Volgian/Ryazanian boundary (the approximate equivalent of the Tithonian/Berriasian boundary). A trend in cooling from the late Jurassic into the Cretaceous is demonstrated by the isotopic composition of the belemnites. The paper is useful for references on Jurassic/Cretaceous palaeoclimatology.]
    Pringle, J., Gore, C.H. and Chatwin, C.P. 1937. Field Meeting at Swindon. Proceedings of the Geologists' Association, vol. 48, [article not found].
    Pruner , P., Housa, V., Oloriz, F., Kostak, M., Krs, M., Man, O., Snabl, P. Venhodova, D., Tavera, J.M. and Mazuch, M. 2010. High-resolution magnetostratigraphy and biostratigraphic zonation of the Jurassic/Cretaceous boundary strata in the Puerto Escano section (southern Spain). Cretaceous Research, vol. 31, issue 2, April 2010, pp. 192-206. Available online 10 November 2009.
    This study summarizes the final results of magnetostratigraphic and biostratigraphic investigations of the Tithonian/Berriasian (J/K) boundary limestones at the locality of Puerto Escaño, Spain. The aim is to prepare the background for correlation of an upper Tithonian and lower Berriasian biostratigraphic zonation with global magnetoevents (manifested in detailed magnetostratigraphic profiles) between the Tethyan and the Boreal realms.
    Magnetostratigraphic studies were applied to an 8.1-m-thick part of the section embracing upper Tithonian and lower Berriasian strata. The average sampling interval was 30 mm. The analysis of the IRM acquisition curves proved the presence of magnetite and hematite, the former mineral being the main carrier of the remanent magnetization. Progressive thermal demagnetization mostly revealed three NRM components, and magnetostratigraphy was based on the directions of the most stable of them, with unblocking temperature varying mostly from 300 to 540 °C. Due to almost parallel beds, the fold test applied to this component did not give convincing results. In contrast, the reversal test received the best classification 'A'. The detected polarity zones could has been unequivocally identified against the M-sequence of polarity intervals drawn from the Geomagnetic Polarity Time Scale 2004. This fact, together with the results of the reversal test, confirmed the ChRM to be the primary component. The sampled part of the section included a part of magnetozone M20r, full magnetozones M20n to M18r and a part of magnetozone M18n. Especially the detection of two reverse respectively by M20n.1r and M19n.1r with thicknesses only 40 and 90 mm, respectively, required much effort when sampling the section. The calculated sedimentation rate varied from 1 to 5 mm/ky.
    The positions of the individual events of tintinnoid biostratigraphy (mainly calpionellids) relative to the global magnetic polarity timescale are precisely defined. The base of the Calpionella Standard Zone, which is considered to be a potential J/K boundary indicator in ammonite-free sections from the Tethyan realm, or in sections where calpionellid stratigraphy applies, lies within magnetozone M19n at the level of 35% of its local thickness. None of the boundaries in the calpionellid zonation coincides precisely with any of those in the palaeomagnetic zonation, but the first appearance datum (FAD) of Calpionella grandalpina Nagy, indicating the base of the Intermedia Subzone, lies in close proximity to the base of magnetozone M19r. The last appearance datum (LAD) for Praetintinnopsella andrusovi Borza in Bed 14A corresponds approximately to the base of the Kysuca Subzone.
    Pugh , M.E. 1969. [in PGA for 1968] Algae from the Lower Purbeck limestones of Dorset. Proceedings of the Geologists' Association, London for 1968, 79, 513-523. By Mary Pugh. See also her M.Sc. Thesis on the Purbeck Group.

    Pugh, W.T. 1954. Report of the Director. Summary of Progress of the Geological Survey for 1953.

    Pugh, W.T. 1958. Report of the Director. Summary of Progress of the Geological Survey for 1957.

    Pugh, W.T. 1959. Report of the Director. Summary of Progress of the Geological Survey for 1958.
    Pushman , D. 1987. Precious Stone of Dorset. Dorset Publishing Company, Sherborne, Dorset. 128 pp. ISBN 0 902129 937. Extract from Forword by Gareth Thomas. " Some books are hard to pin down. They seem to defy easy classification, and I imagine librarians throughout the country struggling to fit them into their Dew, or whatever other, system. -- This is such a book. It is about a part of Dorset, certainly - its people and its out of the way places; and equally certainly it tells us quite a bit about the business of stone, quarried in Purbeck and on Portland, then shaped and transported to all corners of the country. -- But it is much more than this. For the vision which compelled David Pushman to begin writing is that famous monument of Portland Stone in Whitehall, London - the Cenotaph. -- Where, where are the monuments to the industrial dead?" - Extract from text " The cenotaph is in its way a revelation - the world of the invisible - the great empty tomb of mankind."

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    Quest , M. 1985. Petrographic and Geochemical Studies of the Portland and Purbeck Beds of Dorset. Unpublished Ph.D. Thesis, Department of Geological Sciences, Faculty of Science and Engineering, University of Birmingham, England, 347pp. By Martin Quest. Supervised by Professor Tony Hallam; thesis examined by Ian West.
    Synopsis: The Portland and Purbeck Beds (Upper Jurassic - Lower Cretaceous) exposed along the south Dorset coast are examined using a variety of geochemical and petrographic tools in an attempt to elicit diagenetic and palaeosalinity information. Boron in the less than 2 micron illite/total clay correlates well with inferred salinity in the Purbeck and there are important conclusions to be drawn regarding element re-cycling. In the Portland Limestone Formation there is no correlation with salinity, the very low boron concentrations possibly reflecting syn-depositional illite degradation. In the Portland Sand Formation and top-most Kimmeridge the concentration of boron (greater than 250 ppm.) is too high for the inferred marine salinities and probably reflects a mineralogical boron input in the form of glauconite. Petrographic, stable isotope and minor/trace element analysis of the Portland Limestone Formation confirms a very simple diagenetic history compatible with early lithification in the shallow sub-surface meteoric zone. A positive correlation between del 18 O and Sr/Na suggests increased diagenetic stabilisation of carbonates on the swell and eastern basin compared to those in the western basin. An apparent isotope and elemental cyclicity on the Isle of Portland may correspond to variations in eustatic sea level. Isotopic analysis of the Purbeck type-section at Durlston Bay has failed to differentiate between early and late-cemented carbonates. This is probably the result of late (ferroan) cements in the former imparting heavy del 13 C signature. Stable isotope and petrographic work on Middle Purbeck beef has identified a burial diagenetic origin. Petrographic, stable isotope, trace element and XRD work on the dolomites of the Portland Sand Formation rejects a penecontemporaneous origin and suggests that they were formed by the dolomitization of a stabilised (lithified?) low Mg calcite mud. Mg was supplied via evaporatively modified solutions, dolomite formation taking place in a partially isolated diagenetic system. The timing of dolomitization is unclear although there is some evidence that it occurred during a period of low eustatic sea level prior to deposition of the Portland Limestone Formation. In the extreme east of the region, basal Purbeck calcitised evaporites exhibit extreme del 13 C depletion (del 13 C - 25 %) suggesting an origin via bacterial sulphate reduction. Calculations using minor/trace element data indicates that calcitisation occurred within a partially closed environment. The absence of very light carbon values further west may reflect less severe reduction reactions or inorganic calcitisation in an aerobic zone associated with a structural high. End of abstract. [This is a very interesting thesis containing good work which has not been published and is therefore not well-known. The isotopic and other geochemical work in general supports previous petrographic studies. Note the two types of calcitisation in the Broken Beds and top Soft Cap which accord with petrographic evidence. There is much calcitised anhydrite in the east and calcitised gypsum in the west. The bacterial reduction theory brings up the interesting topic of hydrocarbons having once been present in the Broken Beds in certain areas, and this is quite likely. The Portland dolomitisation theory differs from that of Townson (1975) who regarded it as penecontemporaneous.]

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    Radley, J.D. 198? Purbeck and Portland Gastropods. M.Sc. Thesis. True low salinity gastropod faunas in virtual evolutionary stasis since their appearance in the Jurassic. (Much Buckinghamshire Purbeck information . Micromorphic gastropod faunas, of algal meadows ;.Valvata, Hydrobia, Bathrotomaria, Aylesbury, Creamy Limestones, Chilmark Tisbury Ragstones, Shotover)

    Radley, J.D. 2002. Distribution and palaeoenvironmental significance of molluscs in the Late Jurassic - Early Cretaceous Purbeck Group of Dorset, southern England: a review. Pp. 41-51 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268pp. Report from a symposium on the Purbeck Group at the Dorset County Museum, Dorchester, Dorset, March 19-22, 1999. By Jonathon D. Radley, University of Portsmouth and Warwickshire Museum. Abstract: Knowledge of the stratigraphic distribution of Purbeck molluscs in the largely lacustrine to marginal marine Purbeck Group of Dorset, southern England is summarised. The gastropod faunas are well known but the bivalves await detailed documentation. The shell concentrations are largely a result of wave and/or current processes although bivalves are preserved in life position. Comparision with Recent marginal-marine settings suggests that the stratigraphic distribution of Purbeck molluscs reflects long-term palaeoenvironmental change. Some bivalves are interpreted as strongly euryhaline, environmentally-tolerant opportunists. Others, notably those of marine aspect, probably tolerated only restricted salinity fluctuations. Dinosaur tracks throughout much of the succession indicate no significant change in water depth. Hence salinity excursions are attributed mainly to fluctuations in runoff and evaporation, as well as changing barrier porosities and inflow-channel configurations. Amongst the near-marine phases, the Cinder Member provides evidence for attendant sea-level rise. Many upper Middle-Upper Purbeck shell concentrations resemble those of the younger Wealden lacustrine-lagoonal successions and attest to upfaulting or intrabasinal highs and/or of the Cornubian massif in latest Berriasian or ealiest Valanginian times. [This paper includes a valuable listing of mollusc species from the various members of the formation and some of these occurrences are not well-known. Radley discusses some of the shell beds: "The concordant biofabrics of the shell pavements and thinner bioclastic limestones indicate oscillatory flow as the dominant mechanism (Kidwell and Bosence, 1991). This is confirmed by imbricated, stacked and nested shell amongst the densely packed accumulations... The Purbeck shell concentrations reflect varying degrees of time-averaging and environmental condensation... Clements (1973) recognised open, closed and transitional salinity series in the Purbeck Group of Dorset through his studies of the ostracods. Thus the Lower Purbeck Beds are largely 'closed' above the basal strata. Consistently the sedimentological data (West, 1975) indicate a hot, semi-arid, sometimes hypersaline, coastal-lagoonal setting with limited marine influence. This interpretation is supported by the molluscan faunas which comprise low salinity and high salinity assemblages with no intervening influxes of marine taxa...The Middle and Upper Purbeck Beds signify largely 'open' environments (Clements, 1973). Accordingly their molluscan associations indicate salinities within the freshwater-euhaline range. Replaced evaporites are mostly restricted to the 'closed' lacustrine Cherty Freshwater Member.. An outline representation of the broad-scale, member-level salinity changes based on molluscan assemblages is presented in text-fig 1." -- There is much more of interest and the diagram referred to is particularly useful.]
    Rameil, N. 2009. Early diagenetic dolomitization and dedolomitization of Late Jurassic and earliest Cretaceous platform carbonates: A case study from the Jura Mountains (NW Switzerland, E France)Sedimentary Geology, Vol. 212, Issues 1-4, 15 December 2008, Pages 70-85. By Neils Rameil, University of Fribourg, Switzerland.
    Early diagenetic dolomitization is a common feature in cyclic shallow-water carbonates throughout the geologic record. After their generation, dolomites may be subject to dedolomitization (re-calcification of dolomites), e.g. by contact with meteoric water during emersion. These patterns of dolomitization and subsequent dedolomitization frequently play a key role in unravelling the development and history of a carbonate platform. On the basis of excellent outcrops, detailed logging and sampling and integrating sedimentological work, high-resolution sequence stratigraphic interpretations, and isotope analyses (O, C), conceptual models on early diagenetic dolomitization and dedolomitization and their underlying mechanisms were developed for the Upper Jurassic / Lower Cretaceous Jura platform in north-western Switzerland and eastern France. Three different types of early diagenetic dolomites and two types of dedolomites were observed. Each is defined by a distinct petrographic/isotopic signature and a distinct spatial distribution pattern. Different types of dolomites are interpreted to have been formed by different mechanisms, such as shallow seepage reflux, evaporation on tidal flats, and microbially mediated selective dolomitization of burrows. Depending on the type of dolomite, sea water with normal marine to slightly enhanced salinities is proposed as dolomitizing fluid. Based on the data obtained, the main volume of dolomite was precipitated by a reflux mechanism that was switched on and off by high-frequency sea-level changes. It appears, however, that more than one dolomitization mechanism was active (pene)contemporaneously or several processes alternated in time. During early diagenesis, percolating meteoric waters obviously played an important role in the dedolomitization of carbonate rocks that underlie exposure surfaces. Cyclostratigraphic interpretation of the sedimentary succession allows for estimates on the timing of early diagenetic (de)dolomitization. These results are an important step towards a better understanding of the link between high-frequency, probably orbitally forced, sea-level oscillations and early dolomitization under Mesozoic greenhouse conditions.
    Article Outline:
    1. Introduction
    2. Geologic setting
    3. Methods
    4. Results
    4.1. Dolomites
    4.1.1. Type-1 dolomite (matrix dolomite)
    4.1.2. Type-2 dolomite (tidal-flat dolomite)
    4.1.3. Type-3 dolomite (burrow dolomite)
    4.1.4. Void-filling dolomite cements
    4.2. Dedolomites
    4.2.1. Type-1 dedolomite
    4.2.2. Type-2 dedolomite
    5. Discussion
    5.1. Dolomitization - models and evidence
    5.2. De-dolomitization - models and evidence
    5.3. Relation of dolomitization to orbitally controlled sea-level change
    6. Conclusions

    Rasnitsyn , A.P., Jarzembowski, E.A. and Ross, A.J. 1998. Wasps (Insecta: Vespida=Hymenoptera) from the Purbeck and Wealden (Lower Cretaceous) of southern England and their biostratigraphical and palaeoenvironmental significance. Cretaceous Research, 19, 329-391. Abstract with faunal list section omitted: This is the first comprehensive study of the insectan order Vespida (Hymenoptera) in the English non-marine Lower Cretaceous (Purbeck and Wealden strata). The fauna includes various diverse sawflies, parasitoid and aculeate wasps but with the exception of social groups. The stratigraphical occurrence and fossiliferous localities are reviewed by AJR. The wasps are revised, described, and keyed out by APR and EAJ who erect 10 new genera and 35 new species: Undatoma stigmatica sp. nov, U. rudwickensis sp. nov. .... Iwestia provecta gen. et sp. nov. (Sphecidae)... (... continues ...) The Purbeck fauna is more diverse generically and contains a greater number of endemics than the Wealden fauna. The absence of xyelids from the Purbeck and Wealden is consistent with a warm climate. Late Mesozoic vespidan faunas are compared globally (especially with eastern Asia), and four Jurassic-Cretaceous assemblages are recognised: an ephialtitid-praeaulacine or aculeate-free Jurassic type; a Lower Cretaceous baissine type with earlier proctotrupid and later angarospecine subtypes: an Upper Cretaceous armaniid type. The Purbeck-Wealden fauna is baissine with two Jurassic "survivors" but lacks social groups; both assemblage subtypes are represented but the influx of aculeate wasps is accompanied by reduced endemicity and generic diversity possibly indicative of ecological change in the hinterland.
    Rat , P. 1957. Carte Geologique des Pays Basco-Cantabriques entre St. Sebastian et Santander. [A coloured - Geological map of the Basque - Cantabrian country between Saint Sebastian and Santader, northwestern Spain.] 1:200,000. [This shows the Purbeckian and Valanginian near Ramales, southeast of Santander. The author states that "near Ramales, a series of calcareous-sandy strata lies above the Callovian. They contain beds with ostracods, serpulids and spirocyclinas, and correspond to the Purbeckien."]

    Rat, P. 1960. Sur l'age at la nature des couches de base du Wealdien dans la province de Santander et a ses abords (Espagne). [On the age and nature of the beds at the base of the Wealden in the province of Santander and its surround (Spain).] Comptes Rendus des Seances de l'Academie des Sciences, France, t. 251, pp. 2207-2209. [Extract: 1. To the southeasst of Santander, near Ramales, the sandy clay complex does not rest directly on the marine Jurassic. It is effectively separated from the Callovian with Macrocephalites by: a. About 150m of dark brackish beds, limestones or sandy marls, with serpulids, spirocylinas and ostracods (Macrodentina, Cypridea) which he has compared to the Serpulite of Germany and the Purbeckian of England...."

    Rat, P. 1962. Contribution a l'etude stratigraphiques du Purbeckien-Wealdien de la region de Santander (Espagne). [Contribution to the stratigraphic study of the Purbeckian-Wealden of the region of Santander (Spain)]. Bulletin de la Societe Geologique de France, 7th Series, tome 4, pp. 3-12. By Pierre Rat. Abstract: The strata, traditionally named Wealden in the Santander part of the Cantabrian Mountains comprises in reality: 1. a lower sequence partly lacustrine, partly brackish, which rests on the marine Callovian and has fossils such as ostracods and Iberina which lead one to compare it both by age and facies with the Purbeckian. The upper sequence, or Wealden in the strict sense, rarely rests directly on the Callovian. Towards the northwest is the Urgonian Complex. [Graphic logs, charophytes, ostracod photographs, Dictyocythere, and a correlation diagram showing the relationship to the Dorset strata.]

    Rat, P. 1963. A propos du Wealdien cantabrique; transgression et regressions marine climatique. Note de M. Pierre Rat, presentee by M. Pierre Pruvost. [On the Cantabrian Wealden (including Purbeck); marine transgressions and regressions of climatic origin.] Comptes Rendus Academie des Sciences, France, tome 256, pp. 455-457. Seance du Janvier 1963. [Discusses the effect of changes in the rainfall regime, such as an increase in rainfall as producing a seaward movement of the freshwater facies, and thus an apparent regression. With a diagram of this.]

    Rat, P. 1963. Problemes du Cretace Inferieur dans les Pyrenees et le Nord de l'Espagne. [Problems of the Lower Cretaceous in the Pyrenees and the north of Spain.] Sonderdruck aus der Geologischen Rundshau, Band 53, pp. 205-220. Abstract: Through recent publications, the major facts or new trends in the stratigraphy of lower Cretaceous are examined. A considerable extension of emerged areas marks the Upper Jurassic (Post-Callovian). A new paleogeography is thus starting. Henceforth terrigenous deposits (clay and sand) are almost continuously conflicting with a mostly calcareous marine sedimentation. The former are highly dependent on local conditions; the latter, unchanging over long periods in all the Mediterranean areas, is the result of really uniform geographical factors: e.g. Rudist limestones, Orbitolina series. In the course of time, a rather quiet but varied sedimentation (lacustrian, brackish or even marine) precedes, in different places, the dumping of huge quantities of "Wealden" sandstones. Elsewhere the discovery of marine Neocomian changes our views on the Aptian transgression. Lastly the detrital albian occurrence of Utrillas beds seems to be widely spread. A climatic change might be responsible for it.

    Rat, P. and Salomon, J. 1966. Donnes nouvelles sur la stratigraphie et les variations sedimentaires de la serie purbecko-wealdienne au S de Santander (Espagne). By Pierre Rat and Jean Salomon. [New observations on the stratigraphy and the sedimentary variations of the Purbeck-Wealden Series to the south of Santander, Spain.]. Journal not known, pp. 216-217, 16 June, 1966. [Beds with the pellet Favreina and ostracods.]
    Rawson , P.F., Curry, D., Dilley, F.C., Hancock, J.M., Kennedy, W.J., Neale, J.W., Wood, C.J. and Worssam, B.C. 1978. A Correlation of Cretaceous Rocks in the British Isles. Geological Society, London, Special Report 9, 70pp.

    Rawson, P.F. and Riley, L.A. 1982. Latest Jurassic - Early Cretaceous events and the "Late Cimmerian Unconformity" in North Sea areas. American Association of Petroleum Geologists Bulletin, 66, No. 12, December 1982, 2628-2644. Abstract: Several regional or local unconformities occur in the latest Jurassic-Early Cretaceous sequences of the North Sea and adjacent areas. Each may have been identified locally as the "late Cimmerian unconformity," a supposed major break at the base of the Valhall Formation (or R~dby Formation where the Valhall is locally absent). Although a major hiatus (or a condensed sequence) may occur at basin margins or above structural highs, over most of the North Sea the base of the Valhall Formation is isochronous, and conformable with underlying sediments. It is detected on seismic reflection profiles because it represents a widespread fades change marking the late Ryazanian transgression. Most of the unconformities and associated sedimentary and/or biologic events are of eustatic origin and, even in the tectonically active areas of the North Sea, the effects of eustatic sea level changes were never completely masked by local tectonics. Thus, in the modeling of individual oil fields, the possibility of sedimentary breaks occurring can be predicted in part by reference to regional or eustatic events. [This is not specifically on the Purbeck Group of Dorset, but deals with equivalent marine strata further to the northeast. There is a correlation chart showing the Dorset Purbeck. The Later Cimmerian or Late Kimmerian Movements are now well-known to have affected the Purbeck sedimentation in Dorset.]
    Raymond , L.R. 1960. The Pre-Permian floor beneath Billingham, County Durham, and structures in overlying Permian sediments. Quarterly Journal of the Geological Society of London, vol. 116, pp. 297-315. By Leo Richard Raymond, B.Sc., F.G.S.
    The paper discusses the pre-Permian floor beneath Billingham, County Durham, and its regional effect on the overlying Main Anhydrite. Several types of structure exposed by mine workings in the Main Anhydrite are described, and their formation and age considered. The Main Anhydrite and associated beds have been affected by movements on several occasions.

    [This paper discusses down-bulges or downbulges in anhydrite, that are very similar to the structure in Purbeck anhydrite at Durlston Head, Dorset.]
    Reid , C. 1903. The Geology of the Country around Salisbury (explanation of sheet 298). Memoirs of the Geological Survey, H.M. Stationery Office, London, 77pp, By Clement Reid. [This discusses the Purbeck strata of Vale of Wardour, Wiltshire.]
    Reinhardt , C., Wunnemann, B. and Krivonogov, S.K. 2008. Geomorphological evidence for the Late Holocene evolution and the Holocene lake level maximum of the Aral Sea. By Christian Reinhardt, Bernd Wunnemann and Sergey K. Krivonogovc. Geomorphology, vol. 93, Issues 3-4, 15th January 2008.
    During the Holocene the Aral Sea underwent various transgressive and regressive phases of different magnitudes. However, previous work has not yet fully clarified the evolution and chronology of the individual phases. Research presented here throws light on the evolution of the Aral Sea during the past 2000 years. It includes field surveys, tachymetric and DGPS-derived altitude measurements, analysis of sediments from two areas of the northern and southern Aral Basin (Tastubek Bay and Karaumbet Bay), and their correlation with GIS-based lake area models. Geomorphological and sedimentological evidence from the study areas shows a transgression of the Aral Sea around 200 AD, ending at a lake level maximum of 54 to 55 m. After a medieval regression, the lake reached this level again between the late 16th and early 19th century AD. The digital elevation model SRTM-3 was used to estimate a lake size of 72,400 km2 for the lake level maximum.
    Elevated palaeoshorelines, specifically at 72-73 m, are completely absent in the study areas. Local remains of escarpments at elevations of 66 m and 73 m are due to resistant Miocene caprock and are therefore not interpretable as shoreline features.
    [An extract follows concerning beds with Cerastoderma and ostracods. This is to some extent an analogue for the Purbeck Protocardia beds.]
    "The following sequence L2 (164-128 cm) consists of silt/clay (61.5 percent) and less fine sand (38.5 percent). Additionally, Cerastoderma sp. shells and valves of the ostracod species Limnocythere inopinata, Cyprideis torosa, Darwinula stevensonii, Tyrrhenocythere donetziensis as well as Loxoconcha immodulata occur. At 128 cm depth the sediment facies changes to fine sand containing only 3.7 percent grain sizes below 63 microns. This section (F2, 128-50 cm) can be subdivided into three layers. The lowermost part (128-94 cm) contains shell fragments of Cerastoderma sp. At 94 cm there is a characteristic accumulation of Cerastoderma sp. shells, which is similar to accumulations in a small depression at the recent surface. Between 94 and 72 cm depth mud lenses with cracks occur within stratified sands, followed by a cross-bedded layer (72-50 cm). A second major change in the sediment facies occurs at 50 cm (Section L1, 50-20 cm). Up to its top the layer contains 58.1 percent silt/clay, 40.8 percent fine sand and nearly 1 percent medium to coarse sand. The fossil record contains in-situ Cerastoderma sp. shells as well as carapaces of the ostracod species C. torosa, T. donetziensis and L. immodulata. Radiocarbon dating reveals an age of 300 plus or minus 30 yr BP (380 plus or minus 47 cal yr BP, 1570 plus or minus 47 AD) for the lowermost part of section L1. A remarkable fact is that this layer wedges towards shoreline S1 at 54 to 55 m along the wadi course. L1 finishes with an 8-cm thick layer of porous gypsum, which extends into larger pockets locally. The cross-bedded uppermost sediments (Section F1, 20-0 cm) are dominated by small grain sizes, containing 77.1% silt/clay, 22% fine sand and 0.9 percent medium to coarse sand. On top of profile AS7 an accumulation of Cerastoderma sp. shells in a small c.10-cm deep depression can be observed."
    [Aral Sea - Purbeck lake analogue, but Purbecks are not discussed in this paper]

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    Riboulleau , A., Schnyder, J., Riquier, L., Lefebvre, V., Baudin, F., and Deconinck, J-F., 2007. Environmental change during the Early Cretaceous in the Purbeck-type Durlston Bay section (Dorset, Southern England): a biomarker approach. Organic Geochemistry, Elsevier, vol. 38/10, pp. 1804 - 1823. . Available online as a PDF file - Go to (search): Organic Geochemistry, 2007, vol. 38/10, pp. 1804 - 1823. [Re; organic geochemistry of the following Purbeck Group beds (see Clements) of the Durlston Bay section, Dorset: DB39, DB48, DB92, DB93, DB102, DB111, from below the Cinder Bed; with samples DB119, DB130, DB182 from above the Cinder Bed. See their Fig. 2 for relationship to the Durlston Bay log.]
    By Armelle Riboulea, Johann Schnyder, Laurent Riquer, Vincent Lefebvre, Francois Baudin, Jean-Francois Deconinck.
    Abstract The Purbeck-type section (Durlston Bay, Dorset, UK) exhibits littoral lagoonal to lacustrine facies. It shows a gradual climatic/environmental change from semi-arid conditions associated with evaporites at the Jurassic-Cretaceous transition, to a more humid climate at the end of the Berriasian. Though generally organic-poor (total organic carbon, TOC, less than 1.3%), the Durlston Bay section shows an organic rich episode (TOC up to 8.5%) located at the transition from evaporitic to more humid facies. A biomarker study was performed in order to determine the origin of the organic matter (OM) in the section and if changes in organic sources accompanied the general environmental change. The distribution of alkanes, hopanes and steranes indicates that the origin of the OM is mainly algal/bacterial and only changed moderately with the climatic evolution. The saline and anoxic bottom water conditions indicated for most of the samples point to the recurrence of salinity stratification within the basin. A high contribution of odd numbered C23-C31 n-alkanes from algaenan-containing freshwater algae, in particular Botryococcus, is noted for all the samples, despite the low abundance of these organisms in the corresponding palynofacies. This prominence probably results from the high resistance to degradation and the selective preservation of Botryococcus-related lipids. The subtle balance of aridity and freshwater inputs favoured both an abundance of Botryococcus and the development of anoxia, leading to the enhanced preservation of OM during the intermediate climatic episode, while the conditions were less favourable during the semi-arid and more humid episodes.

    Article Outline
    1. Introduction
    2. Material and methods
    3. Results
    3.1. n-Alkanes and acyclic isoprenoids
    3.2. Cyclic and branched alkanes
    3.3. Cyclic isoprenoids
    3.4. Other compounds
    4. Interpretation of biomarker distributions
    4.1. Thermal maturity
    4.2. Origin of OM
    4.3. Palaeoenvironment
    4.4. Depositional model
    5. Conclusions

    [extract - conclusions]
    5. Conclusions
    Analysis of the biomarkers in the apolar fraction of the extracts of nine samples from the Purbeck type section at Durlston Bay (Late Jurassic-Lower Cretaceous, Dorset, UK) was performed. The organic matter (OM) is relatively immature, as revealed by the distribution of alkanes, hopanes and steranes. Its origin is mainly autochthonous, with variable contributions from dinoflagellates, bacteria and freshwater algae, in particular Botryococcus. The contribution of n-alkanes from freshwater algae is high in all the samples, even the most degraded ones, which is attributed to the resistant nature of the lipids produced by these algae. While the sedimentary facies of the Durlston Bay section shows a clear environmental change from evaporitic at the base of the section to more humid conditions at the top, no clear change in primary producers is apparent from the biomarker content. From the distribution of hopanes and presence of gammacerane, hypersaline to saline waters characterise most of the samples, indicating that salinity stratification was amajor process in OM deposition. The gammacerane and homohopane indices show, however, a generally decreasing trend from the base to the top of the section, consistent with the increasing humidity. As proposed by Bohacs et al. (2000) for lacustrine settings, it appears that the best conditions for OM preservation in the estuarine/lagoonal Durlston Bay setting occurred during a period of subtle balance of evaporation and freshwater input. The study has also demonstrated that palynofacies and biomarker analyses are complementary and should be more often associated in palaeoenvironmental studies.

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    Robinson , E. 1998. The stones cry out. Dorset Geologist's Association Newsletter. April 1998. p. 2-3. With Replies from: Environmental Services, County Hall, Purbeck Stone (Carol Foster, Senior Planning Officer, Minerals and Development Control); and from Kingston Lacey and Corfe Castle Estates, Re. Quarrying (J.C. Homer, Esq., Property Manager - Purbeck Estates). These contributions follow from the leading article in the February edition of the DGAG Newsletter - The demise of a tradition.

    Robinson, C.E. 1882. A Royal Warren or Picturesque Rambles in the Isle of Purbeck. By C.E. Robinson, M.A., Barrister-at-Law, Author of the "Cruise of the Widgeon;" "The Golden Hind, Thessale, and Other Poems," etc. The etchings by Alfred Dawson. London, The Typographic Etching Company, 23 Farringdon Street, EC. 1882.

    Etching of Corfe Castle by Alfred Dawson in Robinson (1882)

    The Preface:

    "A Royal Warren"-The words by themselves may perhaps fail to convey the meaning, which renders a seemingly whimsical title really descriptive of the work now before the reader. It should therefore be explained at the outset that the "Isle of Purbeck" -no island in point of fact, but an isolated promontory - was originally, like the New Forest, a wild hunting-ground of our Norman, and probably even Saxon kings. Disafforested so far back as the reign of Henry III, it became thenceforward merely a "Warren of Conies" [a Rabbit Warren]; but the spirit of the antiquated forest laws remained, to hamper the cultivation and improvement of this beautiful district, long purposely secluded from the outer world. To the former operation of these laws the quaint, half-mediaeval character of the island, even at the present day, is in great part due.
    The first requisite of a forest, or warren, is that it should be always kept in a wild, half-peopled, untilled state; and in such a condition for ages were successive kings able to keep the Isle of Purbeck, much assisted by the barriers of heath, hill, and water, which divide it from the rest of Dorsetshire, and by the influence they could wield from the royal castle of Corfe. Hence the old-world aspect of the villages, mansions, and churches, scattered over a country of great natural beauty, which has yet suffered little at the hands of the railway "navvy," the "jerry" builder, or the modern agriculturist. Grand sights in Purbeck may be few, the massive ruins of Corfe Castle and the magnificent coast scenery notwithstanding; but, on the other hand, it is a perfect storehouse of picturesque subjects on a smaller scale. This has been recognised by distinguished artists long before now. Turner visited and worked in the island; the late E. W. Cooke, R.A., left several drawings of Purbeck views behind him; and Mr. Seymour Haden has etched many charming subjects there. It is the lead of such pioneers as these that the Author has endeavoured with his pen and the Artist with his pencil to follow, in the course of the rambles described in this volume. The fruit of their joint labour is neither a county history, a diary of travel, nor a guide-book (though it shares the nature of all three), but a series of pen-and-pencil sketches of the picturesque element in Purbeck, and any special value it may possess is owing to the fact that most of the materials for the letterpress, as well as the plates and cuts, were gathered at one and the same time, in the heart of the country depicted, and thus may be said thoroughly to illustrate one another.
    Although the first place has throughout been given to the picturesque, many pages have been reserved for whatever is of greatest interest in the historical, topographical, or antiquarian lore relating to the locality; and here the author must acknowledge his indebtedness to the Purbeck section of that well-known book, Hutchins's History of Dorset (Ed. 1861), which was almost entirely rewritten by Mr. Thomas Bond, M.A., J.P., of Tyneham House (a member of one of the oldest and most respected families in the district), and constitutes a model in its department of research. References to it are frequently made in this volume, as also to the monographs by the same author, entitled respectively, "The Ancient Manor Houses" and" The Ancient Families of Purbeck." Recourse has also been had to that interesting work of the Right Hon. George Bankes, M.P., The Story of Corfe Castle (published by John Murray, 1853); and to several other books not peculiarly of local interest. To Mr. A. M. Luckham are owed some notes referring to Studland.
    Nor has natural history been entirely disregarded. The author has been enabled, by the kindness of Mr. R. H. Soden Smith, of the South Kensington Museum; to add an interesting note on the land-molluscs of Purbeck; and is indebted to Mr. Henry Willett for a communication of the results of his recent exploration in Durleston Bay, Swanage, and rediscovery of remains of the rare fossil mammal, Triconodon mordax.
    This information may all be regarded as supplementary to that contained in the county-history, Hutchins's Dorset, and the author himself has been able to bring forward fresh matter in the descriptions of scenery, generally, throughout the book; and particularly in the accounts of Swanage and Studland, of the wrecks of the Wild Wave and other vessels, of the stone quarries, and Tilly Whim, and of antiquities found at Swanage and elsewhere.
    The work will, therefore, it is hoped, be considered of local interest; while, in describing the picturesque features of such a thoroughgoing bit of old England as Purbeck still remains, the author trusts also to gain the ear and suffrage of the general public.
    It is proper to mention that the ten large plates, and smaller etchings or cuts, from the hand of Mr. A. Dawson (son of the well-known landscape painter, the late Mr. Henry Dawson of Nottingham) are all new, and all original (except the map, and two geological sections, and the cut of the guardship at South-haven, which is from a sketch by the Author).
    Some of the large views are copper-plate artists' etchings of the old type, executed by the well-known process of drawing with a needle on copper, through a blackened varnish, or "ground," and then obtaining incised lines by applying acids, in solution, to the uncovered parts of the copper. The others are produced by a method in some respects novel, to which the name "photograving" may conveniently be applied. An ordinary photographic negative is taken from the artist's drawing, which is then impressed by the action of light on the gelatinous substance, portions of which being subsequently dissolved away, the remainder present a delicate relief mould. From this mould an electrotype in copper is taken, which forms the face of the finished plate. The effect aimed at is that of copper mezzotint. These plates, as well as the etchings, are printed tn a roller press. The small cuts are practically etchings, until they leave the artists' hands, for they are so far executed in the same manner, but through a white prepared ground on brass plates. Here, however, the resemblance is at an end, since no acid is used, but all the parts of the drawing which are intended to be white in the impression, are raised by adding wax, and the whole is then electrotyped in copper, so that the lines, instead of being incised, are in relief. After the electrotype has been backed with lead and mounted on a block of wood, these blocks can be printed exactly as ordinary woodcuts, along with the letter-types of the book-printer. This process, invented by Mr. A. Dawson, is the subject of a patent, and is known as "Typographic Etching." It is as well adapted for fine picturesque work as for reproducing mechanical drawings, for which purpose it has been greatly used; and being, as compared with wood cutting, inexpensive, yet equally lasting, has no doubt an important future.
    C. E. R.
    16 Old Square, Lincoln's Inn, 9th January 1882.

    Rodrigues , N., Cobbold, P.R., Loseth, H. and Ruffet, G. 2009. Widespread bedding-parallel veins of fibrous calcite ('beef') in a mature source rock (Vaca Muerta Fm, Neuquen Basin, Argentina): evidence for overpressure and horizontal compression. Journal of the Geological Society, London, Vol. 166, 2009, pp. 695-709. By Nuno Rodrigues, Peter R. Cobbold, Helge Loseth and Gilles Ruffet.

    Abstract: In the Neuquen Basin of Argentina, 'beef' (bedding-parallel veins of fibrous calcite) is widespread within Late Jurassic black mudstones. A typical vein consists of two grey inner zones and two white outer zones. The inner zones contain inclusions of wall rock and hydrocarbons. Calcite fibres are perpendicular to the margins. In the outer zones, the angle between fibre and margin varies from about 45 degrees at the vein tips to 90 degrees in the centre. Imprints of fossils are offset, proving that the fibres have grown antitaxially. We infer that the veins opened in two phases. During Phase 1, the opening was vertical, against gravity. During Phase 2, the veins resisted tectonic shortening, so that shear stresses acted at the margins. The senses of shear account for the fibre angles. At outcrop, igneous intrusive rocks have cut and metamorphosed the veins. From burial curves, maturity calculations, growth strata, and ages of igneous intrusions, we estimate that the inner zones of the beef formed in the oil window, during the Aptian to Albian, and that the outer zones formed in the gas window, during the Cenomanian to Campanian. We infer that the beef is evidence for fluid overpressure during hydrocarbon generation.

    [example of text - first part of Introduction]
    'Beef' is an old quarryman's term for bedding-parallel veins of fibrous calcite. These are common in some sedimentary basins,especially in black mudstones that are rich in organic matter and carbonates. Sorby (1860) described beef in coastal exposures of Jurassic strata (the 'Shales-with-Beef') in SW England. There are other occurrences in Great Britain (Marshall 1982), the USA (Franks 1969; Tobin et al. 1996), Canada (Mackenzie 1972; Al-Aasm et al. 1992, 1996), the Falkland Islands (Tarney & Schreiber 1976; Maillot & Bonte 1983), France (Becq-Giraudon 1990), Germany (Jochum et al. 1995), the North Sea (Hillier & Cosgrove 2002), the Czech Republic (Suchy et al. 2002), Eastern Siberia (Kolokol'tsev 2002), Venezuela (Macsotay et al. 2003), Mexico (Fischer et al. 2005) and Trinidad and Tobago (http://www.gstt.org/Geology/cone%20in%20cone.htm). In undisturbed sedimentary basins, veins of beef tend to be bedding-parallel and horizontal, whereas the fibres tend to be vertical. These fibres yield information about the kinematics and mechanics of opening. The fibres appear to have grown vertically, during progressive opening of the veins. More generally, for fibrous veins of any attitude, there is a consensus that the fibres have grown incrementally, partly or totally tracking the history of relative displacement of the walls (Taber 1918; Durney & Ramsay 1973). The infilling mineral seems to have acquired its fibrous habit during progressive opening, especially if the host rock is porous. In some examples, opening and infilling seem to have occurred episodically, by a crack-seal mechanism (Ramsay 1980). In other examples, growth appears to have been more continuous (Taber 1918; Durney & Ramsay 1973; Means & Li 2001). In crack-seal, the fibrous mineral fills an open micro-crack (Ramsay 1980), whereas in Taber growth, there is no open micro-crack, but a cohesive boundary between fibre and substrate. However, the details are subject to debate. For example, Means & Li (2001) could not exclude the possibility that micro-cracks formed during their physical experiments, in which they reproduced Taber growth of fibrous minerals in veins. Also in fibrous veins, crystal faces between neighbouring fibres tend to be smooth, not serrate, and this may indicate a lack of growth competition (Mugge 1928; Urai et al. 1991). Hilgers et al. (2001) numerically modelled the growth of fibres by crackseal, and estimated that growth competition is inhibited when the crack width is less than about 10 microns. According to the positions of the growing crystals with respect to the walls, Durney & Ramsay (1973) distinguished three kinds of fibrous veins: (1) in stretched veins, fractures open and seal repeatedly in different positions across the vein; (2) in syntaxial veins, fibres grow on one or both sides of the vein and towards the middle of the vein, where a fracture is inferred; (3) in antitaxial veins, the fibres grow from a median suture line towards the walls. Our current understanding is that the fibrous minerals in veins grow by precipitation, mainly from supersaturated aqueous solutions, as a result of chemical reactions or changes in physical conditions, especially of temperature and pressure. There are two potential mechanisms for transporting the nutrients (Elburg et al. 2002). Advective fluid flow transports them over long distances, until they precipitate in a vein, which is effectively an open system (McCaig et al. 1995). Alternatively, the nutrients diffuse over shorter distances (centimetres to decimetres), in what is effectively a closed system (Durney & Ramsay 1973; Oliver & Bons 2001). It should be noted that the assumption of an open or closed system depends on the scale of observation. Horizontal fractures may be a result of high pore fluid pressures (Stoneley 1983). These are common in sedimentary basins, especially at depth (Swarbrick et al. 2002). The term overpressure refers to a condition in which the fluid pressure is greater than that of an equivalent free column of water. The possible causes of overpressure are a matter for debate." [continues ..]

    [This paper is very useful for understanding the origin of Purbeck beef]

    Ross , A.J. and Vannier, J. 2002. Crustacea (excluding Ostracoda) and Chelicerata of the Purbeck Limestone Group, southern England: a review. Pp. 71-82 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268pp. Report from a symposium on the Purbeck Group at the Dorset County Museum, Dorchester, Dorset, March 19-22, 1999. By Andrew Ross, The Natural History Museum, London and Jean Vannier, Universite Claude Bernard Lyon 1, Villeurbanne, France. Abstract: Three orders of Crustacea, apart from the Ostracoda, are represented in the Purbeck Limestone Group of southern England: the Isopoda, Conchostraca and Decapoda. Two species of isopod have been recorded: Archaeoniscus brodiei Milne Edwards and a single specimen of Cyclosphaeroma woodwardi Van Straelen. However, examination of the specimen of C. woodwardi has shown that it is from the Portland Group and not from the Purbeck Limestone Group. Archaeoniscus brodiei is abundant at one horizon just above the Cinder Bed in the Vale of Wardour, Wiltshire, which Brodie called the Isopod Limestone. Four species of conchostracans have been recorded: Liograpta subquadrata (J. de C. Sowerby); L. jurassica Novozhilov; Brachygraptus wardourensis Novozhilov; and Pseudograpta andrewsii (Jones). The order Decapoda is represented by two unidentified species belonging to the families Erymidae and Coleiidae. One chelicerate specimen is known, belonging to the subclass Xiphosuria. Associated ostracods indicate that it came from the base of the Purbeck Limestone Group or the Portland Group. It is identified as Mesolimulus sp. and constitutes the second xiphosuran record for the Mesozoic of the UK.
    Rossinsky , V. Jr., Wanless, H.R. and Swart, P.K. 1992., Penetrative calcretes and their stratigraphic implications, Geology, 20 (1992), pp. 331-334.
    Ruffell , A.H. and Rawson, P.F. 1994. Paleoclimate control on sequence stratigraphic patterns in the Late Jurassic to Mid Cretaceous, with a case-study from Eastern England. Palaeogeography, Palaeoclimatology, Palaeoecology, 110, 43-54. Abstract: Sediment supply is a fundamental control on the architecture of sedimentary sequences. In clastic depositional environments, the volume of sediment being transported into the basin of deposition is strongly dependent on both the nature of the weathering regime in the hinterlands, and on runoff. During arid, low sea-level phases in the late Jurassic and early-mid-Cretaceous, clastic supply was reduced and long hiatuses became common at sequence boundaries or during maximum flooding. These hiatuses amalgamated where sediment starvation produced strongly condensed ("super-condensed") sections. In intervening humid, higher sea-level phases, clastic supply was more abundant: hence thick sediment packages separate sequence boundaries, downlapping surfaces should be apparent on seismic sections, and condensed sections become rare. Where carbonate deposition dominates over clastic, sediment formation is largely intrabasinal and the effects of palaeoclimate on sequence stratigraphy are less obvious. Knowledge of palaeoclimates may lead us to search for certain sequence stratigraphic patterns connected to changes in sediment supply.

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    Salter, D.L. and West, I.M., 1965. Calciostrontianite in the basal Purbeck Beds of Durlston Head, Dorset. Mineralogical Magazine, 35, 146-150. By Donald Salter and Ian West. [Calciostrontianite, the calcium and strontium carbonate, from alteration of celestite in the evaporitic Broken Beds at Durlston Head, Swanage, Dorset. This is a follow-up from the paper of West (1960) on celestite or celestine at Durlston Head.]
    Schindler , T., Wuttke, M. and Poschmann, M. 2008. Oldest records of freshwater sponges (Porifera: Spongillina) - spiculite finds in the Permo-Carboniferous of Europe. Palaontologische Zeitschrift, 2008, Vol. 82/4, p. 373-384, Stuttgart, 31-12-2008. 7 figures and 1 table.
    Abstract: Up to now the oldest freshwater siliceous sponges are known from Jurassic deposits of Europe and North America. In this paper stratigraphically older Permo-Carboniferous freshwater siliceous sponges are reviewed/reported. Largely overlooked occurrences originate from the French Massif Central (Stefanian B), new discoveries come from the Saar-Nahe Basin (Stefanian C and Autunian) in south-west Germany. All Permo-Carboniferous finds originate from freshwater lake deposits situated hundreds of kilometers away from the sea. Preserved are monaxone spicules (oxeas) of various length/diameter ratios partly concentrated to spiculites. Gemmoscleres have not been found. A taxonomic classification on family level is not possible. Reasons for the immigration of marine euryhaline sponges into the freshwater might be the consequence of the newly developed freshwater biotopes on Pangaea after the Variscan Orogeny. Possible migration routes are rivers connecting inland basins with the sea.
    [includes a brief comment about Purbeck freshwater sponge remains - Spongilla purbeckensis.]
    Schnyder , J., Baudin, F. and Deconinck, J-F. 2005. A possible tsunami deposit around the Jurassic-Cretaceous boundary in the Boulonnais area (northern France). Sedimentary Geology, 177, Issues 3-4, 209-227. By Johann Schnyder, Francois Baudin and Jean-Francois Deconinck.
    Abstract: An unusual succession of facies locally deposited around the Jurassic-Cretaceous boundary in the Boulonnais (northern France) is attributed to a tsunami event by comparison with recent tsunami deposits. This sedimentary succession includes basal erosion with reworked lithified blocks, soft-sediment deformations, an erosional conglomerate overlain by wood fragments and clays containing continental and marine fossils in one setting and conglomerate with mixed fauna in an other setting. The tsunami probably affected the coast of the Boulonnais area of the London-Brabant Massif. The origin of the event is unknown. It was most probably triggered by an earthquake, but other origins such as volcanic eruptions, a giant landslide, or even the impact of an extraterrestrial bolide into the ocean may also be considered. [Position within the Purbeck sequence is not certain but it is near the J/K boundary and some evaporites are present. Thus by comparision with Dorset it is likely to be Lower (perhaps to Middle) Purbeck and not equivalent to the Stair Hole liquifaction bed (Upper Purbeck) which is probably a seismite of earthquake origin.]

    Schnyder, J., Baudin, F., Deconinck, J-F., 2007. Occurrence of organic-matter-rich beds in early Cretaceous coastal evaporitic setting (Dorset, UK): a link to long term palaeoclimate changes? Cretaceous Research, Published by Elsevier, Volume 30, Issue 2, April 2009, pp. 356-366. By Johann Schnyder, Francois Baudin and Jean-Francois Deconinck. Available online.
    In Dorset (southern U.K.), the Durlston Bay and Lulworth Cove sections expose lowermost Cretaceous coastal marine and non-marine partly evaporitic sediments (the so-called Purbeckian facies). An interval with organic matter (OM)-rich layers is recognized in both sections. This OM-rich interval is 20 m thick in the middle of the Durlston Bay section. Within these beds, a large OM accumulation is recorded, with total organic carbon (TOC) of up to 8.5 wt percent. High hydrogen index (HI) values (up to 956 mgHC/gTOC) point to a Type I OM, generally considered as derived from algal-bacterial biomass. This contrasts with the OM present in the underlying and overlying intervals, displaying in general lower TOC and HI values, and consisting of degraded algal-bacterial material with higher proportions of terrestrial OM. This organic-rich accumulation can be interpreted as a period of enhanced primary productivity within coastal lagoonal/lacustrine settings at times of low sea level. It could also correspond to increasingly reducing waters. The OM distribution found in Dorset correlates well with existing long-term palaeoclimatic patterns, i.e. a latest Jurassic (late Tithonian)-Early Cretaceous (early Berriasian) semi-arid climate replaced during the middle-late Berriasian by a more humid climate. This pattern is recorded elsewhere on both margins of the Tethys, indicating a widespread climate change. In Dorset, deposition of OM-rich beds occurs exactly at the transition between these two climate regimes, probably during the first increase in humidity, which led to enhanced freshwater supply into coastal lakes and lagoons. This suggests a direct or indirect climate control on local development of primary productivity and/or anoxia/dysoxia within restricted shallow coastal water masses. The proposed environmental model links OM production and preservation with a changing, climate-driven, hydrological regime. [end of abstract]

    Schnyder, J., Ruffell, A., Deconinck, J-F and Baudin, F. 2006. Conjunctive use of spectral gamma-ray logs and clay mineralogy in defining late Jurassic-early Cretaceous palaeoclimate change (Dorset, U.K.). By Johann Schnyder (Universite Paris), Alistair Ruffell (Queen's University, Belfast), Jean-Francois Deconinck (Universite de Bourgogne) and Francois Baudin (Universite Paris). Palaeogeography, Palaeoclimatology, Palaeoecology, 229, (4), Jan 2006, 303-320. Available online from Elsevier - Science Direct. Abstract: Detrital clay mineralogy is controlled by weathered source rock, climate, transport and deposition that in turn influence the spectral gamma-ray (SGR) response of resultant sediments. Whilst a palaeoclimate signal in clay mineralogy has been established in some ancient successions, the SGR response remains contentious, largely because the data sets have yet to be collected at the same or appropriate vertical scales to allow comparison. In addition, the influence of organic matter on SGR is not always considered. Here, we present clay mineralogical, total organic carbon (TOC) and SGR analyses from the late Jurassic and early Cretaceous of the Wessex Basin, a period of previously documented palaeoclimate change. The aim of this paper is to estimate the sensitivity of SGR as palaeoclimatic tool, SGR and clay mineral data having been collected at the same sample points, making this one of the most rigorous comparison of clay mineral and SGR to date. Overall, the correlation between high thorium/potassium or thorium/uranium and kaolinite associated with a well-established palaeoclimate change shows that elevated thorium may be used as a proxy for humid palaeoweathering, as suggested by few previous studies. [end of abstract]. Keywords: spectral gamma ray; clay; clay mineralogy; palaeoclimate; Purbeck facies; Jurassic; Cretaceous; Jurassic-Cretaceous boundary; thorium; Dorset; England.

    Schnyder et al., 2005 J. Schnyder, G. Gorin, M. Soussi, F. Baudin and J.-F. Deconinck, Enregistrement de la variation climatique au passage Jurassique/Cretace sur la marge sud de la Tethys: mineralogie des argiles et palynofacies de la coupe du Jebel Meloussi (Tunisie centrale, formation Sidi Kralif). Bulletin de la Societe Geologique de France, 176 (2) (2005), pp. 171-182.
    Schudack, M. and Schudack, U. 2002a. Late Kimmeridgian to Berriasian palaeogeography of the northwestern Iberian Ranges (Spain). Berliner Geowissenschaftlichen Abhandlungen A, 106, 445-457.

    Schudack, M. and Schudack, U. 2002b. New biostratigraphical data for the Upper Jurassic of Asturias (Northern Spain) based on ostracoda. Revista Espanola de Micropaleontologia, 34, 1-18.
    Sellwood , B., Wilson, C. and West, I.M. 1990. Jurassic sedimentary environments of the Wessex Basin. 13th International Sedimentological Congress, Field Trip Guide A16. 89p.
    Shearman , D.J. 1966. Origin of marine evaporites by diagenesis: Institute of Mining and Metallurgy, Transactions, 75, B 717, 208-215. [Purbeck evaporites of the Warlingham Borehole. This is a classic paper.]

    Shearman, D.J. 1971. Marine Evaporites: the calcium sulfate facies: American Society Petroleum. Geologists seminar, University of Calgary, Canada, 65pp.
    Sigogneau-Russell , D., Hooker, J.J. and Ensom, P.C. 2001. The oldest tribosphenic mammal from Laurasia (Purbeck Limestone Group, Berriasian, Cretaceous, UK) and its bearing on the 'dual origin' of Tribosphenida. Comptes Rendus de L'Academie des Sciences, Series 2, Fascicule A, Sciences de la Terre et des Planetes, 333 (2), 141-147. Abstract: We report the discovery of a tribosphenic molar in the Purbeck Limestone Group, Early Cretaceous. southern England, which we attribute to a new taxon, Tribactonodon bonfieldi gen.n. sp.n. In addition to the fact that it represents the oldest unequivocal tribosphenic mammal known from Laurasia, this tooth shows characters which have an important bearing on the distinction between the two infraclasses of Holotheria (Australosphenida and Boreosphenida) as defined by Luo et al., and which lead us to question the timing and place of their emergence.
    Silva , L.J.H.D. 2001. (or D'El-Ray Silva, 2001? - I am not sure which is correct) Structures in Jurassic rocks of the Wessex Basin, southern England - II diapirism in evaporite layers. By Luiz Jose Homem D'El-Ray Silva. Revista Brasileira de Geociencias, 31(l): pp. 75-82, March 2001. Universidade de Brasilia - Institute de Geociencias - Campus Universitario, Asa Norte, 70.910-900, Brasilia, DF, Brazil - e-mail: ldel-rey@unb.br.

    This paper should not be taken seriously because the famous Purbeck stromatolites or thrombolites surrounding the remains of fossil trees at the Fossil Forest are described within it as evaporitic diapers! This is not a minor error: the paper is so erroneous and with such neglect of previous literature that it should not have been published in a serious journal.

    Complete paper is available on the internet free as a PDF file, or search with Google.
    Abstract: The Jurassic Purbeck Beds of the Fossil Forest cliff, Lulworth Cove (southern England) encloses a ~ 10 m-thick wedge in which four juxtaposed levels (L2-L5) of differential strain have been characterized, between two levels of non deformed rocks (LI and L6). Within the zone of strain, level L2 comprises basal calcareous marls displaying 1 cm-thick zones of bed-parallel foliation developed in an anastomosed pathway to form pillow-like features, and upper layers of evaporite where tens of mushrooms or diapirs are observed. They commonly display a~ 1 m-sized circular geometry on bed-parallel sections, a ~0.5 m high central zone forming a generally bed-perpendicular tail, and are surrounded by rim synclines where the evaporite layers are entrapped together with chert and shale; level 3 consists of evaporite and shales displaying cm to dm-scale extension and contraction structures; level L4 comprises remnants of evaporite layers embedded in a shale matrix - a tectonic melange; and level L5 comprises blocks of evaporite and limestone involved in a shale / argillite matrix, a limestone breccia (the so-called Broken Beds) inside which some layers are still preserved and exhibit 1-10 m-scale contraction and extension structures. Level L5 results from the westwards displacement of a wedge above an extensional detachment (the interface L3 / L4) and below another detachment established on a layer of shale at the contact with level L6. The mushrooms clearly deform the L3 / L4 detachment and are interpreted as thermal convection structures formed by a progressive down-sucking of the layers back in the direction of an imaginary point at the center of the diapirs - a centripetal suction leading to contraction and coeval extension, soon after initial displacement of the wedge. The pillow-like features result from percolation of fluids across the marls simultaneously with the evolution of the mushrooms. Keywords : Diapirism, structural analysis, Purbeck Group, thermal convection, salt tectonics
    RESUMO: No afloramento Fossil Forest da localidade de Lulworth Cove, no sul da Inglaterra, a Formacao Purbeck (Jurassico) engloba uma cunha (espessura ~ lOm) de rochas divididas em quatro andares verticalmente justapostos, os quais diferem quanto a estilos / intensidade de deformacao (L2-L5) e ocorrem encaixados entre dois andares de rochas nao deformadas (LI e L6). O andar L2 consiste, na base, de margas carbonaticas que exibem zonas de 1-2 cm de espessura nas quais a rocha e foliada e que se dispoem de modo a formar um padrão anastomosado ou em almofadas e, no topo, de camadas de evaporitos exibindo dezenas de estruturas na forma de cogumelos (ou diapiros) que tem geometria normalmente circular (~lm de diametro) em secoes paralelas ao acamamento, e que normalmente exibem uma zona tubular central com cerca de 0.5 m de altura, formando uma chamine ou cauda perpendicular as camadas; tais estruturas sao comumente circundadas por dobras sinclinais asimetricas e apertadas, na zona interna das quais o evaporito, folhelho e chert sao trapeados e deformados. O andar L3 consiste de evaporitos e folhelhos afetados por estruturas compressionais e extensionais de escala sub-metrica; o andar L4 consiste de fragmentos de camadas de evaporito misturados caoticamente em matriz de folhelhos, ou seja, tipica melange tectonica; e o andar L5 apresenta camadas brechadas de evaporito e calcareo, com intercalacoes de folhehos e argilitos, todas afetadas por estruturas compressionais e extensionais de escala = l 0 metros. O andar L5 resulta do deslocamento, para oeste, das camadas superiores da cunha ao longo e acima de um descolamento extensional estabelecido na interface dos andares L3 e L4, e abaixo de um outro descolamento estabelecido ao longo de camada de folhelho no contato com o andar L6. Os cogumelos do andar L2 claramente deformam o descolamento L3 / L4 e sao, portanto, estruturas tectonicas, aqui interpretadas como devidas a processo de conveccao termal que teve lugar logo apos o deslocamento inicial das rochas acima da interface L3/L4. Em consequencia do processo convectivo, as camadas foram sugadas para baixo e para tras, em direcao a um ponto imaginario no centro dos diapiros - uma especie de succao centripeta responsavel pela formacao simultanea de estruturas contracionais e extensionais. Simultaneamente, formaram-se as almofadas da base do andar L2 por percolacao de fluidos atraves das margas. Palavras-chave : Diapirismo, analise estrutural, Purbeck Group, conveccao termal, tectonica de sal
    Introduction: The area surrounding the locality of West Lulworth, southern England (see geological map and cross section in the Introduction to the companion paper) has specially charmed geologists, as the rocks that form its substratum - limestones of the Upper Jurassic Portland-Purbeck Beds, and the Cretaceous argillites, arenites (Wealden Group), gault, greensands and chalk, as well as Tertiary (Paleogene) sands, gravel and clays - contains well-exposed important geological features around Lulworth Cove, such as: two megasequence boundary unconformities, hm-scale folds that affect Wealden Group rocks and constitute the Lulworth crumple (to the west of the cove), and the Broken Beds plus a series of mushroom structures recorded within the Purbeck Group that crop out along the Fossil Forest cliff, to the east of the cove (West 1975, Underhill & Paterson, 1998). The Upper Jurassic Purbeck Group, or Purbeck Beds, consists of carbonate and clay sediments (West 1975). The detailed structural analysis presented in the companion paper has allowed to show that, at the Fossil Forest cliff, the Purbeck Group encloses a ~10 m-thick wedge of highly deformed rocks divided in four juxtaposed structural levels (L2-L5) situated above non deformed limestones (level LI) and below non deformed limestones with intercalated shales / argillites (level L6). Structural level L2 comprises basal calcareous marls displaying 1 cm-thick zones of bed-parallel foliation developed in an anastomosed pathway to form pillow-like features, and upper layers of evaporite plus chert / shale deformed around the mushrooms. Level 3 consists of evaporite and shales displaying cm- to dm-scale extension and contraction structures such as boudinage, domino- and listric-style normal faults; a bedding sub-parallel foliation affected by recumbent folds; and thrust faults as well as asymmetric folds verging either to the west or to the east. Level L4 comprises remnants of evaporite layers and fragments of these layers embedded in a shale matrix, a typical tectonic melange. Level L5 (the so-called Broken Beds) comprises = 1m-sized blocks of evaporite and limestone involved in a shale / argillite matrix (a typical limestone breccia) and also some still preserved layers exhibit 1-10 m-scale contraction and extension structures such as asymmetric folds, thrust, and planar- and listric-style normal faults. The detailed description of the structures led to the conclusions that: (1) - Structural level L5 results from the westward displacement of a wedge above a top-down to the west extensional detachment established on levels L3 and L4 and below a detachment established along a layer of shale at the contact with level L6. The Broken Beds formed by intense fracturing associated to inter-layer slip and also to the folding that resulted from this slip; (2) - The westward displacement may be part of a more regional tectonic event, if one considers that the close spatial relationship of the Broken Beds and the evaporite layers, at the Fossil Forest cliff, is remarkably noticed across several localities of the Dorset coast, according to a detailed description in West (1975); (3) - The displacement of the wedge took place earlier in the Alpine inversion of the Wessex basin, that ended the tilting of Purbeck Beds to the north. The chaotic structure of the breccia was finally attained by further slip associated to this latter tilting; (4) - The record of varied style and intensity of strain, even for adjacent parts of a single layer or in juxtaposed structural levels makes the Fossil Forest outcrop a key field locality for understanding crustal deformation processes that have been described in recent literature (summary in Axen et al. 1998); and (5) -The east-west flow along the basal evaporite detachment was followed in time by the north-south compression of the whole area, implying in a vertical juxtaposition of nearly orthogonal kinematics that may fit in the transpression-related Cenozoic inversion of European basins (Ziegler 1989). [continues]

    Simpson , G.G. 1928. A Catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum, Trustees of the British Museum, London, 215 pp.

    Simpson, G.G. 1959. Mesozoic mammals and the polyphyletic origin of mammals. Evolution, 13, 405-414.
    Sladen , C. P. 1983. Trends in Early Cretaceous clay mineralogy in NW Europe. Zitteliana, 10, 349-357.

    Sladen, C.P.and Batten, D.J. 1984. Source-area environments of Late Jurassic and Early Cretaceous sediments in southeast England. Proceedings of the Geological Association, London, 95, 149-163.


    [STEART et al. 2014. Wardour Purbeck Cone Paper.]

    Steart, D.C., Spencer, A.R.T., Garwood, R.J., Hilton, J., Munt, M.C., Needham, J. and Kenrick, P. 2014. X-ray Synchrotron Microtomography of a silicified Jurassic Cheirolepidiaceae (Conifer) cone: histology and morphology of Pararaucaria collinsonae sp. nov. (By: David C. Steart, Alan R.T. Spencer, Russell J. Garwood, Jason Hilton, Martin C. Munt, John Needham and Paul Kenrick). PeerJ, online in Open Access. Published 23rd October 2014.
    We document a new species of ovulate cone (Pararaucaria collinsonae) on the basis of silicified fossils from the Late Jurassic Purbeck Limestone Group of southern England (Tithonian Stage: ca. 145 million years). Our description principally relies on the anatomy of the ovuliferous scales, revealed through X-ray synchrotron microtomography (SRXMT) performed at the Diamond Light Source (UK). This study represents the first application of SRXMT to macro-scale silicified plant fossils, and demonstrates the significant advantages of this approach, which can resolve cellular structure over lab-based X-ray computed microtomography (XMT). The method enabled us to characterize tissues and precisely demarcate their boundaries, elucidating organ shape, and thus allowing an accurate assessment of affinities. The cones are broadly spherical (ca. 1.3 cm diameter), and are structured around a central axis with helically arranged bract/scale complexes, each of which bares a single ovule. A three-lobed ovuliferous scale and ovules enclosed within pocket-forming tissue, demonstrate an affinity with Cheirolepidiaceae. Details of vascular sclerenchyma bundles, integument structure, and the number and attachment of the ovules indicate greatest similarity to P. patagonica and P. carrii. This fossil develops our understanding of the dominant tree element of the Purbeck Fossil Forest, providing the first evidence for ovulate cheirolepidiaceous cones in Europe. Alongside recent discoveries in North America, this significantly extends the known palaeogeographic range of Pararaucaria, supporting a mid-palaeolatitudinal distribution in both Gondwana and Laurasia during the Late Jurassic. Palaeoclimatic interpretations derived from contemporaneous floras, climate sensitive sediments, and general circulation climate models indicate that Pararaucaria was a constituent of low diversity floras in semi-arid Mediterranean-type environments.
    [Keywords: Purbeck, trees, cone, cones, Jurassic, Pararaucaria, Cheirolepidaceae, Wardour, Chicksgrove, Tisbury, Needham, John Needham, Kenrick, Paul Kenrick, Steart, David Stearn, Great Dirt Bed, thrombolite, pine cones, Dirt Bed, Lulworth, dirt, limestone, group, microtomy, synchroton, Natural History Museum, semi-arid, Portesham]
    "The Cheirolepidaceae were a distinct and diverse group of conifers. They are well documented through an extensive Mesozoic fossil record that includes foliage, wood cones and most notably pollen of Classopolis type (references ...). Many species were large trees, but the family is thought to encompass a broad range of growth forms, including woody shrubs and possibly herbs. Due to the fragmentation of parts, however, direct evidence of habit is rare (reference). In contrast to the modern conifers, Cheirolepidaceae were widespread in coastal environments at low to mid palaeolatitudes, especially during the Cretaceous Period (reference). Evidence from sediments and cuticle morphology, most notably the sunken papillate stomata (reference), indicate that many were adapted to xeric habitats and that they grew in brackish coastal meres (reference) on the margins of freshwater rivers and lakes (reference). In fact their ecological dominance in these environments was a unique and distinctive feature of late Mesozoic floras (references). Many aspects of Cheirolepidaceae morphology and habit remain poorly understood. In particular the structure of the ovulate cones has proven difficult to discern due to a predominance of compression fossils, sometimes with internal cuticular membranes preserved (references). Permineralised cones have only recently been recognised, providing important new insights into their internal tissue systems (references). ....[continues]
    [For some reason, the paper does not discuss the several, similar, silicified cones from similar basal Purbeck strata, the Great Dirt Bed equivalent, at Portesham Quarry, Dorset found by West (1961) and described by: - Barker, D., Brown, C.E., Bugg, S.C. and Costin, J. 1975. Ostracods, land plants and Charales from the basal Purbeck Beds of Portesham Quarry, Dorset. Palaeontology, vol. 18, part 2, pp. 419-436. In addition, a male cone was found by Francis in the same bed at Godnor Quarry, Isle of Portland, Dorset, and referred to in Francis (1983). Apparently the Portesham material may be referred to in subsequent paper. ]
    Sorby , H.C. 1860. On the origin of " cone-in-cone ". British Association for the Advancement of Science, Report of the 29th Meeting, 1859. Transactions of Sections, Geology, p. 124. [on the subject of beef]
    Stevenson , W. 1812. General View of the Agriculture of Dorset.
    Strahan , A. 1898. The Geology of the Isle of Purbeck and Weymouth. Memoirs of the Geological Survey, England and Wales. 278pp. By Sir Aubrey Strahan. [There are interesting chapters on the Purbecks, but they are out-of-date in many respects. Note that some of the content is the same as in Woodward (1895) - Jurassic Rocks of Great Britain, vol. 5, and a section of this is reproduced below.]
    Strasser , A. 1986. Ooids in Purbeck limestones (lowermost Cretaceous) of the Swiss and French Jura. Sedimentology, 35, 711-727.

    Strasser, A. 1988. Shallowing-upward sequences in Purbeckian peritidal carbonates (lowermost Cretaceous, Swiss and French Jura Mountains). Sedimentology, 35, pp. 369-383.

    Strasser, A. 2009. Milankovitch Cyclicity and High-Resolution Sequence Stratigraphy in Lagoonal-Peritidal Carbonates (Upper Tithonian-Lower Berriasian, French Jura Mountains). In Orbital Forcing and Cyclic Sequences (eds P. L. de Boer and D. G. Smith), Blackwell Publishing Ltd., Oxford, UK.
    Three sections of the Tidalites-de-Vouglans and Goldberg Formations have been studied in the French Jura. The sedimentary record consists of well-stratified carbonates which represent shallow-lagoonal, intertidal and supratidal depositional environments where salinities ranged from normal marine to hypersaline or fresh water. The beds display a hierarchical stacking which is probably related to climatically induced sea-level fluctuations in the Milankovitch frequency band. Elementary sequences (commonly corresponding to an individual bed) would represent the 20-ka precession cycle, larger composite sequences the 100- and 400-ka eccentricity cycles.
    Elementary and larger sequences can, partly and on a small scale, be analysed in terms of sequence stratigraphy. Sequence boundaries mark the top of the beds and in many cases are erosive. Low-stand deposits comprise calcrete, conglomerates and marls with freshwater fossils, or are missing altogether. Thin transgressive deposits follow a generally well-defined transgressive surface and contain reworked pebbles and mixed marine and freshwater fossils. High-stand deposits make up the bulk of the sequences and generally exhibit a shallowing-upward facies evolution. A large part of the sea-level cycle, however, was dominated by non-deposition, reworking and erosion. The time framework given by the inferred Milankovitch cyclicity permits estimation of rates of sediment accumulation and of diagenetic processes.
    Detailed analysis of depositional sequences interpreted to have been induced by Milankovitch cycles suggests a duration of about 3.6 Ma for the two formations studied. Larger sequences are difficult to identify, but partial time control by ammonites and charophyte-ostracod assemblages allows for a tentative correlation with the global sea-level chart of Haq et al. (1987). Difficulties with and the validity of such a comparison are discussed.
    Suttle , E.W., Brown, P.A., Oppe, E.F. and White, H.J. 1962. Track of a Dinosaur: Iguanodon - type, biped, 3-toed. Unpublished hand-out sheet circulated in Dorset in 1962. Copy in the possession of Ian West. Extracts: "13 imprints of each foot extending uninterruptedly westward for a distance of 25-26 feet (7.6 m to 7.9 m) exposed on the quarried surface of Pink Bed in Purbeck Roach [i.e. the pinkish, partially oxidised top of the most important quarried stone in the "Middle Purbeck" or Durlston Formation, bed no. 125 of Clements' Durlston Bay log], Nov-Dec. 1961. At Messrs J. and E.W. Suttle's Swanage quarry (The quarry is on high ground above the top end of Hillsea Road, Herston, Swanage, Dorset). [Parallel tracks are shown diagrammatically with footprints heading to 254 degrees, i.e. WSW.] .. The footprints, naturally varying in state, are shewn stylised as being perfectly isolated and wholly familiar in local character, i.e. medium-size, 3-digit footprints of which numerous specimens are preserved, commonly from the Purbeck Roach. .. Pink Bed is the bottom layer of several slabs or slats which form Purbeck Roach to a typical thickness of up to 2 feet (0.6 m). Pink Bed stone varies from 5 inches (13 cm) to almost none or 'dirt', and in this and other instances registers the bottom, lowest, compression of the mud originally trodden [i.e. an undertrack, beneath and parallel to a track or impression in a higher lamina or layer]." By E.W. Suttle, Langton Matravers; P. Anthony Brown, Corfe Castle; E.F. Oppe, Worth Matravers; and H. John White, Swanage. [A local record of the Suttle's Quarry discovery, important in drawing attention to the find. The initial interpretation of the two trackways as a single one made with left and right feet of a dinosaur was later corrected by Charig and Newman (1962) to a theory of two nearly parallel trackways. A third trackway was also found. Charig also questioned the Iguanodon interpretation. ]
    Swaine, J. 1962. Iguanodon footprints. New Scientist, No. 276, A letter. 1st March 1962. [parallel dinosaur tracks at Swanage, Dorset, in Mutton Hole quarry, active at that date.]. By Mr. John Swaine of Swanage - not a serious technical comment because of discussion of an incline. [This includes a small sketch map showing part of the quarry and three tracks, two of them alongside each other. The tracks are all parallel, apparently trending SSE towards NNW. Go to: Charig and Newman (1962), which shows the tracks discussed by Swaine, and also Suttle et al. (1962)above.]
    Sir. - The short stride [2 ft and 4 ft spacing shown on sketch map] of the Iguanodon, whose footprints were discovered in a quarry [near Swanage] known locally as "Mutton Hole" (New Scientist, Notes and Comments, 25th January 1962) may be accounted for by the animal walking up a steep incline [this incline is not feasible because of lagoonal sedimention!]; its weight clearly taken on the "ball" of the foot. Where the depressions left are up to 2 inches deep, the heel marks are so shallow as to be barely distinguishable. One cannot visualise a very large specimen making these tracks - something in the two to three ton size.
    What is of considerable interest and has apparently been overlooked is a second set of eleven separate footprints of the same size and shape going in the same direction on a parallel course about 10 feet to the right, as the sketch shows. John Swaine. 31 Kings Road, Swanage.
    [My informal comment: This parallelism of tracks has been seen in dinosaur tracks elsewhere in Dorset, e.g. Isle of Portland. The dinosaurs seem to have had a herd-like behaviour. As in the cases of horses, the front of the dinosaur foot seems to have pushed down and back. The heel only goes down when they are stationary. The dinosaurs in Dorset seem to have generally travelled on wide mud-flats in a straight line, often as a herd, and at a good steady pace, but not very fast.]

    For information on the subject of dinosaur tracks and the movement of dinosaurs go to:
    Kuban: An Overview of Dinosaur Tracking. You will note that some theropods did actually run, but I am not aware that any evidence of this has been seen in Dorset. Check the Ensom and Delair publications on dinosaur footprints, listed in this bibliography.

    Sylvester Bradley, P.C.
    [The Late Professor P.C. Sylvester Bradley ["Sylvester-Bradley"], or Peter Bradley, once Head of the Department of Geology at Leicester University. Dorset geologist, ostracod palaeontologist and author of many papers on the Purbeck Group, or Purbeck Formation, as it was know at that date. The "Sylvester" was not hyphenated to Bradley, but was sometimes used in this way in the geological literature, and the hyphen may or may not be omitted in references.]

    Sylvester Bradley , P.C. 1940. The Purbeck beds of Swindon. [re The Town Gardens Quarry, Swindon, Wiltshire] Proceedings of the Geological Association, London, 51, 349-372. [interesting low salinity facies, compare with Portesham basal Purbecks.] By Professor Peter C. Sylvester Bradley, B.Sc., F.G.S.
    Extracts from Introduction:
    "In 1936 Fitton, in his well-known paper "On the Strata between the Chalk and the Oxford Oolite" observed that the indications of Purbeck strata at Swindon were "inconsiderable". Eleven years later, however, P.B. Brodie described the beds in some detail. He noted about thirteen feet of freshwater strata resting on a greatly denuded surface of Portland beds, and collected a number of fossils. Of these he listed Paludina [Viviparus], Planorbis, Cypris, and a few badly preserved insects, the scales and teeth of fish and saurian, "Thuytes" and small seed vessels
    [note incidently that seeds are also found at Portesham, Dorset, which has some similarities of facies and similar ostracods to Swindon - see West, (1961). [West, I.M. 1961. Lower Purbeck Beds of Swindon facies in Dorset. Nature, London, 190, 526. and see the subsequent paper by Barker et al. (1975) ].
    Forbes, in his report to the British Association noted that he had inspected the section, and R.A.C. Austen (later 'Godwin-Austen') described in 1850, how Forbes and himself, had, together with Prestwich and others, set out on an excursion through Berkshire and Wiltshire. The party examined the "great quarry" of Swindon and Austen came to some very noteworthy conclusions in his report. He described a limestone "containing a bed about 1 foot thick almost entirely composed of Terebra Portlandica, Sow. [i.e. Aptyxiella portlandica, the very well-known "Portland Screw" fossil] overlying twenty-five feet of sands and sandstones (with "Cardium dissimile" [i.e. the well-known, Purbeck Protocardia purbeckensis of the Hard Cockle Member etc.]). This when traced upwards, was found to pass into a freshwater limestone. "Above this" he added "are bands of of clays and calcareous sandstones. The whole constituting the freshwater portion of the series.... With the dip of the beds south, these disturbedd bands of clays and sands are seen to be surmounted by layers of tranquilly deposited sandstones in layers interstratified with sands, and in these the forms of the marine Portland reappear [i.e. interdigitation of Portland and Purbeck facies].
    From this evidence he deduced that the freshwater beds were the geological equivalents of some portion of the "Wealden" and that this "is not as has hitherto been represented, a freshwater accumulation of an area of dry land subsequent to the oolitic period but was contemporaneous with the Portland, and perhaps even with older portions of the oolitic series [i.e. Jurassic]". In a footnote he referred to the beds as "the fluvio-marine strata at the top of the Portland." [continues with history of geological research at Swindon]....
    Robert Damon in 1860 not only noted "dirt beds" [i.e. Purbeck rendzina palaeosols] at Swindon but also recorded occasional [silicified] tree stumps in an erect position [i.e. like those of the Fossil Forest and Isle of Portland, Dorset]. ......
    In 1876, on the occasion of another excursion of the Geologists' Association to Swindon, Charles Moore gave a description of the researches which he had made on the Purbeck beds during the previous fifteen years, and on which he had already made a preliminary report to the Wiltshire Archaeological and Natural History Society three years before [actually 1874]. A remarkable list of fossils, most of which Moore seems to have obtained from the various "dirt beds" [i.e. palaeosols, but perhaps more like the "Middle Purbeck", Durlston Bay, Mammal Bed in facies, rather than the basal Purbeck, Lulworth Formation, dirt beds which are unfossiliferous apart from plants, because of penecontemporaneous weathering, but with the fossiliferous Portesham Great Dirt Bed, the exception].
    "[At Swindon] Three species of mammals were recorded, various reptiles, "the oldest known true frog", plant remains, many molluscs, "four or five species of Cypris" [i.e. ostracods including Cypridea dunkeri which also occurs at Portesham or Portisham. See West], two species of foraminifera and "rarely the spines of an echinite [echinoid]" ......
    "Towards the east of the quarry the so-called Purbeck Beds overlie the Portland Beds in considerable force, and the black carbonaceous friable loam, in which Mr. Moore has found so many fossils, is well developed at this point. Almost the first fragment which that gentleman split with his hammer was found to contain a fine tooth of Goniopholis, the Swanage Crocodile. Further on the same bed was found to be a mass of Cerithium Portlandicum [Aptyxiella portlandica] the shell itself (not the cast [internal mould]) being preserved in dark friable marly grit. But the most noteworthy circumstances here is that, above this bed, the regular Portland limestone comes in again rich in casts [moulds] of the usual Portlandian shells, showing most clearly how 'Portland' and 'Purbeck' conditions inosculated [interdigitated] at this spot, and that if names are to be ridgidly adhered, without reasonable modification of their meaning, according to local circumstances, we actually have the Portlandian overlying the Purbeck on the east side of the quarry at Swindon [in modern terms this is simpley a matter of diachronous facies - imw]. [continues with mention of the work of Keeping, 1879]." [end of small extract here]


    Sylvester Bradley, P.C. 1949a. The ostracod genus Cypridea and the zones of the Upper and Middle Purbeckian. Proceedings of the Geologists' Association, 60, 125-151. By P.C. Sylvester-Bradley, B.Sc., F.G.S. Received 14th November 1947.
    Summary: The nomenclature of the genus Cypridea is clarified, and a valid genolectotype is selected. The shell characters of the genus are described. Stratigraphically significant species of the Upper and Middle Purbeck Beds are described, and their distribution incorporated in a revised zonal scheme.
    With Appendix:
    A Section of the Purbeck Beds at Poxwell.
    Poxwell Cutting (30/741834), Dorset.
    (From a section measured in 1936-38 with the help of Mr Brian Mottram. Dr. W.J. Arkell kindly allowed me to compare my section with that which he measured for the Geological Survey Memoir. He also identified the gastropods. Professor T.M. Harris identified the Charophyta. The unnamed ostracods are to be described in due course by Mr. F.W. Anderson. The zonal arrangement follows that proposed by the author.)
    [There is a good, detailed listing of 50 beds with their faunal content. The succession is well-described and could be compared in detail with the well-known Clement's Log of the Durlston Bay Purbeck sequence. Most of the log at Poxwell is concerned with Middle Purbeck and only a small part of the uppermost Lower Purbeck is included. See also Arkell (1947) where a shorter version of a log of the Poxwell Road Cutting is given. This has less detail and lists 31 beds.]


    Sylvester Bradley, P.C. 1949b. A section of the Purbeck Beds at Poxwell. Proceedings of the Geologists' Association, London, 60, 151-3. See above. [Middle Purbecks with ostracods, beef, charophytes etc. Parts of this are still exposed.]

    Sylvester Bradley, P.C. 1964. [or 1962, as listed in Clements, 1993?] Type sections of the Bathonian, Portlandian and Purbeckian stages and the problem of the Jurassic-Cretaceous boundary. Colloque du Jurassique, Luxembourg, 1962, pp. 259-263.


    Sztejn , J. 1991. Ostracods from the Purbeckian of central Poland. Acta Palaeontologica Polonica, 36, 115-142.

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    Taitt, A.H. and Kent, P.E. 1958. Deep Boreholes at Portsdown (Hants) and Henfield (Sussex). British Petroleum Company Limited, London.
    Boreholes through Purbeck anhydrite etc.
    Thomas , J. 1998.Discover Dorset: Stone Quarrying. The Dovecote Press Ltd., Stanbridge, Wimborne, Dorset. 79pp. Paperback. 4 pounds,95 pence. ISBN 1 874336 61 X. Stone quarrying is the most important of Dorset's traditional industries, with a history that reaches back to Roman times. The limestones from the Isles of Purbeck and Portland are amongst the most famous of all building stones, but elsewhere in the county there were once thousands of smaller quarries providing stone for the surrounding region. Their legacy lives on in Dorset's parish churches, country houses, farmhouses and cottages - even whole villages, giving each area its own distinctive character. Jurassic limestones, the heathstones, sandstones and Greensand - even flint and chalk - all have combined to the architectural patchwork that makes Dorset so attractive. (from the back cover). [Pp 55-64 - on Purbeck limestone, with details of buildings in which it is used.]

    Thomas , J. 2008. Dorset Stone. Dovecote Press, by Jo. Thomas, 128pp. ISBN 978-1-904-34963-1. Price (2009) 17 pounds, 95 pence. A very well illustrated (colour illustrations) guide book to the building stones of Dorset, their geological origins and their use in historic buildings. This is a very readable book with a good select bibliography. For Purbeck limestones see p. 61 et seq.

    Townson, W.G. 1971. Facies Analysis of the Portland Beds. Unpublished. D.Phil. thesis, Oxford University., 284pp.

    Townson, W.G. 1975. Lithostratigraphy and deposition of the type Portlandian. Journal of the Geological Society of London, 131, 619-638. (Key Paper by Dr. W.G. Townson, Geoff. Townson)

    Townson, W.G. 1976. Discussion of Portlandian faunas. Journal of the Geological Society of London, 132, pp. 335-336.

    Townson, W.G. and Wimbledon, W.A. 1979. The Portlandian strata of the Bas Boulonnais, France. Proceedings of the Geologists' Association, vol. 90, issues 1-2, pp. 81-91.
    The Marine Portlandian strata in the Bas Boulonnais are c. 20 m thick, comprising the argillaceous glauconitic Assises de Croi overlain by the calcareous quartzose of the Gres des Oies. These are succeeded by a thin 'Purbeckien' algal limestone, the Calcaire des Oies (1 m), overlain by 'Wealdien' clays and sands (10–20 m?). The Kimmeridgian/Portlandian boundary (sensu anglico) lies within the basal few metres of the Assises de Croi and not at the Tour de Croi Nodule Bed as previously thought. The lower four Portlandian ammonite zones (Albani to Kerberus) are now proven to be present up to the Middle Gres des Oies, enabling correlation with England. The 'Purbeckien' limestone and 'Wealdien' clays are interpreted as non-marine Portlandian deposits and the 'Wealdien' sands as Lower Cretaceous in age. The Portlandian strata comprise an overall regressive sequence deposited in environments ranging from middle neritic to lacustrine.

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    Underhill , J.R. 2002. Evidence for structural controls on the deposition of the late Jurassic- early Cretaceous Purbeck Limestone Group, Dorset, southern England. Pp. 21-40 in: Milner, A.R. and Batten, D.J. (Editors) 2002. Life and environments in Purbeck times. Special Papers in Palaeontology, No. 68, Palaeontological Association, London, 268pp. Abstract: Integration of field studies with subsurface data demonstrate that deposition of the late Jurassic - early Cretaceous Purbeck Limestone Group occurred under semi-arid conditions during an important phase of syntectonic extensional activity in the Wessex Basin. Use of structural restorations and neotectonic analogue studies support the introduction of a new model to account for the regional and local along-strike variability in deposition of the Purbeck Limestone Group. It is proposed that the segmented nature of the episodically-active, basin-bounding Purbeck Fault explains observed thickness and sedimentological variations, including lateral facies changes and clast reworking. In addition to affording a tectonic framework in which to understand the rich palaeontological assemblages, the new depositional model also provides a mechanism for explaining the rapid death and unusual preservation of conifer forests through rapid submergence following co-seismic activity on the normal fault system. [By John R. Underhill, Department of Geology and Geophysics, University of Edinburgh.]

    Underhill , J.R. and Stoneley, R. 1998. Introduction to the development, evolution and petroleum geology of the Wessex Basin. In: Underhill, J.R. (Ed.) Development, Evolution and Petroleum Geology of the Wessex Basin. Geological Society, London, Special Publications, 133, 1-18.

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    Vera, J.A. and Jimenez de Cisneros, C. 1993 Palaeogeographic significance of black pebbles (Lower Cretaceous, Prebetic, southern Spain), Palaeogeography, Palaeoclimatology Palaeoecology, 102 (1993), pp. 89-102.

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    Walkden , G., and E.F. Oppe. 1969. In the Footsteps of Dinosaurs. The Amateur Geologist, vol. 3, pt.2.
    Watson , J. 1977. Some Lower Cretaceous conifers of the Cheirolepidaceae from the U.S.A. and England. Palaeontology, 20, 715-749.

    Watson, J. and Alvin, K.L. 1999. The cheirolepidiaceous conifers Frenelopsis occidentalis Heer and Watsoniocladus valdensis (Seward) in the Wealden of Germany. Cretaceous Research, 20, 315-326. Abstract: The cheirolepidiaceous conifer Frenelopsis occidentalis Heer has been identified for the first time from the Wealden in the Lower Cretaceous of Germany. Proof of the occurrence of alternating whorls of three leaves in this species confirm its attribution to the genus Frenelopsis Schenk, which was previously tentative. Branches emerging in mid-internode are seen for the first time in F. occidentalis. A piece of a core from the Wilsnack 2 borehole contains short lengths of conifer shoots in which decurrent leaf bases are separated laterally by distinct sutures along the entire length of the internode. Most of the shoots display the opposite decussate leaf arrangement typical of the form-genus Cupressinocladus Seward but there is a single shoot in which the leaves occur in alternating whorls of three. The cuticle suggests identification with the species Cupressinocladus valdensis (Seward) from the English Purbeck and Wealden which has recently been reassigned to the newly erected cheirolepidiaceous genus Watsoniocladus Srinivasan.

    Watson, J. and Lydon, S.J. 2004. The bennettitalean trunk genera Cycadeoidea and Monathesia in the Purbeck, Wealden and Lower Greensand of southern England: a reassessment. Cretaceous Research, vol. 25, Issue 1, February 2004, pp. 1-26. By Joan Watson and Susannah J. Lydon.
    The history of the discovery of the Lower Purbeck dirt-beds on the Isle of Portland and the silicified bennettitalean trunks occurring within these fossil soils is reviewed and discussed. In the absence of the original type material, neotypes are selected for the two poorly-defined Purbeck species Cycadeoidea megalophylla Buckland and Cycadeoidea microphylla Buckland. A third cycadeoid trunk species, Cycadeoidea gigantea Seward, from higher in the Portland Purbeck sequence, is reassigned to the genus Monanthesia Wieland ex Delevoryas, the use of which is discussed in relation to the genus Cycadeoidea Buckland. Synonymies are presented for both genera and for all the more or less recognisable named species from the English Lower Cretaceous. Newly collected specimens from the Isle of Wight support the view that loose beach specimens of Cycadeoidea and Monanthesia trunks, formerly considered to be from the Wealden, are actually from the Lower Greensand. It is suggested that additions to our knowledge of English cycadeoid trunks can only be achieved by the use of invasive techniques, which are recommended for the further study of type specimens.

    (re occurrence of cycadeoid trunks in the basal Purbeck of Portland. They seem to have been mainly found in the Lower Dirt Bed, but some have come from the Great Dirt Bed, and one at 14 ft (4.3m) or 17 feet (5m.) above the Great Dirt Bed. This is stratigraphically somewhere near the Hard Slatt or Hard Cockle Member with dinosaur footprints at Coombefield):

    "Unfortunately, very few of the museum trunks are accurately provenanced, usually labelled "Cycadeoidea, Dirt-bed, Portland", so that we have been unable to identify a single trunk known to be from the Lower Dirt Bed. In 1895 a large, columnar type of cycadeoid trunk was discovered at a higher horizon in one of the Portland quarries and subsequently described by Seward (1897) as Cycadeoidea gigantea (Fig. 9A-D, discussed below under Monanthesia). Seward (1897, p. 22, fig. 1) gives stratigraphic details and relates that it was found horizontally in a bed of shaly clay 2 feet thick, about 17 feet above the Great Dirt Bed, "in one of Mr. Barnes's quarries close to St. George's Church on the west side of the old Portland Wide Street." Strahan (1898, p. 84) repeats this information and names the discoverer of the trunk as Mr. A. M. Wallis, but gives the height above the Great Dirt Bed as 14 feet. The measurements in the sketch of the section given by Seward, A.C., 1897. On Cycadeoidea gigantea, a new cycadean stem from the Purbeck Beds of Portland. Quarterly Journal of the Geological Society of London 53, pp. 22-39 5 pls. .Seward (1897, fig. 1) actually add up to 15 feet 9 inches between the Great Dirt Bed and the shaly clay with the trunk. St. George's Church can be seen in Fig. 3, which shows Bower's Quarry face in July 2002, labelled using the quarrymen's terminology found in the old literature and with the probable stratigraphic level of C. gigantea marked. In this quarry, conifer stumps are encountered not uncommonly but the quarry manager Mr. Mark Godden (pers. comm. 2002) has not seen a single Cycadeoidea in 25 years of quarrying. There is the possibility that the occasional find goes unrecorded with the specimen removed as a curiosity but it is clear that the dirt beds are not being quarried at present in an area where dense fossil forest is preserved."
    [This is a good account and there is more information like this; see the full paper.]
    Webster , T. 1816. in: Englefield, Sir H.C. 1816. A Description of the Principal Picturesque Beauties, etc., of the Isle of Wight. With additional observations on the strata of the Island, and their continuation in the adjacent parts of Dorsetshire, by T. Webster. Payne and Foss, London.

    Webster, T. 1826. Observations on the Purbeck and Portland Beds. Transactions of the Geological Society, London, 2, 37-44.
    Weissert , H. and Mohr, H. 1996. Late Jurassic climate and its impact on carbon cycling. Palaeogeography, Palaeoclimatology, Palaeoecology , 137, 189-203.

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    WEST, Ian Michael, of Romsey Hampshire and Southampton University, geologist, webpage author and compiler of this webpage.

    West , I.M. 1960. On the occurrence of celestine on the Caps and Broken Beds at Durlston Head, Dorset. Proceedings of the Geologists' Association, 71, 391-401. By Ian M. West.
    Abstract: An occurrence of celestine in the Lower Purbeck Beds at Durlston Head is described and shown to be of syngenetic origin. Deposition probably took place near the margin of a basin of evaporite deposits into which strontium solutions were introduced. At a later date the celestine has been involved both in the brecciation that formed the Broken Beds and in complex local faulting. [This record of strontium minerals was the first definate evidence of former evaporites in the Broken Beds. It supported the hypothesis of Hollingworth (1938) that gypsum or anhydrite were once present at this horizon. The precise origin of the celestite, however, was not well-understood at that time, and it was later shown to be a replacement of evaporites (connected with groundwater flow up the fault-plane) and not syngenetic. See West (1973; 1975). The cliff section (fig. 2) is of a downbulge into former evaporites, and is a relatively complex part of the Durlston Bay cliffs that is not easily interpreted at first sight. Two celestite horizons are present, but the palaeosols of the Lulworth area are not properly developed here because this locality is in the "basinal" facies of the Purbecks. Since this paper was written celestite has been found in the Purbecks in the Soft Cockle Member of Durlston Bay and the Isle of Portland, in the Caps and Broken Beds at Worbarrow Tout and at Stair Hole. Calciostrontianite also occurs at Durlston Head (Salter and West, 1965).]

    West, I.M. 1961. Lower Purbeck Beds of Swindon facies in Dorset. Nature, London, 190, 526.
    Extract: ' .. a marl has been discovered with a fauna resembling that of the freshwater facies of the 'Swindon Series'. In the well-known Portisham [or Portesham] quarry with the 'fossil elephant' [stromatolitic limestone around a tree trunk], the tree-foot "impure marls with seams of chert" listed by Woodward as occurring 9 feet, 6 inches above the Portland Stone have been found to contain the Swindon ostracod Ulwellia papulata Anderson, and well-preserved charophytes in abundance. Gastropods are also abundant and perhaps have Swindon affinities... continues. [The fauna and flora discovered in the Portesham Charophyte Chert was subsequently described by Barker, D., Brown, C.E., Bugg, S.C. and Costin, J. 1975. Ostracods, land plants [including cones and seeds], and charales of the basal Purbeck Beds of Portesham Quarry. Palaeontology, 18, 419-436.]

    West, I.M. 1964a. Evaporite diagenesis in the Lower Purbeck Beds of Dorset. Proceedings of Yorkshire Geological Society, 34, 315-330. By Ian M. West of Southampton University.
    [Petrographic evidence of vanished evaporites in the Caps and Broken Beds - pseudomorphs, celestite, lutecite etc. Diagenetic history established.] Abstract: Five stages have been determined in the diagenetic history of the calcium sulphate beds of Lower Purbeck age in Dorset, particularly by reference to abundant pseudomorphs and other relict textures and structures preserved in late-formed gypsum and in secondary silica and calcite. The weight of the overburden is thought to have controlled the changes. Occurrences are described of minerals, including celestite, calciostrontianite, lutecite and quartz remaining after the removal in solution of gypsum. A description is also given of secondary limestones which occur particularly in the Caps and Broken Beds. They are shown to be almost entirely replacements of original sulphate deposits. [End of abstract].
    Below are shown lenticular pseudomorphs after gypsum of the type described in this paper.

    Pseudomorphs after gypsum in chert

    Pseudomorphs after gypsum in oolite of the Hard Cap


    West, I.M. 1964b. Deformation of the incompetent beds in the Purbeck Anticline. Geological Magazine. 101, p.373. By Ian M. West. [Origin of the Lulworth Crumples in the Upper Purbecks - short note. Discusses disharmonic folding at the base of the incompetent beds - in this case the Wealden strata just above the Upper Purbeck. The short note supports Strahan's (1898) view that Lulworth Cove was in a region of compression. ]

    West, I.M. 1964c. Age of the Alpine Folds of Southern England. Geological Magazine, 101, No. 2, 190-191. [This short note discusses the slow development of the so-called Alpine folds of southern England, as opposed to older views of relatively rapid folding. With regard to the Purbecks there is brief mention that the Tertiary "Bagshot" gravels of Black Down (Hardy's Monument) and Moreton in Dorset contain pebbles of Purbeck chert and limestone (Reid, 1896 and Arkell, 1947). Later work has supported the main theme of this short note.]


    West, I.M. 1965. Macrocell structure and enterolithic veins in British Purbeck gypsum and anhydrite . Proceedings of the Yorkshire Geological Society, 35, 47-58. Abstract: A nodular structure, here termed "macrocell structure" [nodular or chicken-wire structure] , is commonly associated with enterolithic veins in the British Purbeck gypsum and anhydrite. The veins and macrocell structure preceded the brecciation that gave rise to the Broken Beds and were present in early secondary anhydrite. Both structures probably originated when primary gypsum was undergoing compaction before the lithification of the associated marl, and have not resulted from hydration of anhydrite. A sequence of diagenesis for Purbeck calcium sulphate with macrocell structure is established, comparable to that previously elaborated [West, 1964a] for the calcium sulphate with [the microscopic] net-texture. Similar features are present in other calcium sulphate deposits.

    Diagram showing postulated diagenetic history of nodular and other gypsum, Purbeck Group, Dorset and Sussex, by Ian West, 1965

    West, I.M. 1969. Contribution in International Field Symposium on the British Jurassic; Guide for Dorset and South Somerset. Ed. H.S. Torrens, A60-61.

    West, I.M. 1973. Vanished evaporites - significance of strontium minerals. Journal of Sedimentary Petrology, 43, 278-279. By Ian West. [A short note, reproduced in full beneath]

    In a recent paper, Folk and Pittman (1971) have clearly indicated the importance of the lutecite and quartzine varieties of chalcedony as evidence for the former presence of evaporites. Although lutecite (fig. 1) has been successfully employed by the present writer for the detection of former gypsum deposits removed by dissolution (West, 1964; West, Brandon and Smith, 1968), confirmatory evidence is usually necessary. Fortunately those processes which cause the removal of evaporites in solution frequently also result in their partial replacement by other minerals.
    Groundwater with bicarbonate ions may partly convert calcium sulphate deposits to calcium carbonate before dissolution of any remaining gypsum. Examples of such calcitized evaporites have been described by West (1964), Shearman and Fuller (1969) and other authors. In a dolomitic succession the calcitic nature of such replacements may be conspicuous. Pseudomorphs, relics of anhydrite in euhedral quartz crystals, and traces of net-texture (West, 1964) or nodular structure (West, 1965) may be present in any replacements or residues of dissolved evaporites. A positive indication of the former presence of calcium sulphate is the occurrence of celestite. This mineral is rarely found in sedimentary deposits other than evaporites, replaced evaporites or insoluble residues of evaporites. The related mineral barite is not so restricted. Associations of celestite with present or former evaporites have been described by Lacroix (1897), Zaritsky (1961), West (1964), West, Brandon and Smith (1968) and many other authors. Celestite is, in most cases, formed by the replacement of gypsum or anhydrite; it is much less soluble than those minerals. It is usually formed by selective removal of strontium ions from groundwater by reaction with deposits of calcium sulphate.

    Lutucite pseudomorph after a lenticular crystal of gypsum, Lower Purbeck, Durlston Bay, Dorset

    FIG. 1. Lutecite pseudomorph after a lenticular crystal of gypsum. Adjacent moulds have been left by the dissolution of gypsum crystals. Lower Purbeck Beds, Durlston Bay, Dorset. Partly crossed polars. X 43.

    Water containing a large proportion of calcium ions and a small proportion of strontium ions most commonly exists where limestone deposits occur in proximity. Celestite beds of appreciable thickness may be thus formed, particularly at the upper or lower boundaries of gypsum or anhydrite deposits. Such diagenetic formation of celestite is most favoured where there is an appreciable flow of groundwater. Continuing diagenesis in a bicarbonate-rich environment may convert celesrite to calciostrontianite (Salter and West, 1965).

    Small-scale occurrences of celestite may be produced by a similar mechanism where gypsum veins have penetrated into limestone. Examples occur in the marine Portland Stone of Dorset where eelestite casts of fossils are replacements of gypsum or anhydrite which has penetrated down from the overlying Purbeck Beds.

    Fig. 2. Lutecite spherulites in celestite. Basal Purbeck gypsum deposit. Mountfield Mine, Sussex. Partly crossed polars. X 36.

    Similarly in Rhaetic limestones [Penarth Group, Trias] of southern England gypsum veins originating from underlying Triassic strata have been converted to celestite.

    Thus, there are many criteria for indicating the former presence of evaporites and it is wise to employ at least two. The occurrence of strontium minerals together with length-slow chalcedony (fig. 2) [and/or lutecite] provides reliable evidence of the former presence of evaporites.

    [REFERENCES (for this paper only; continue down for main reference list )
    [-- Folk, R. L. and Pittman, J. S., 1971. Length-slow chalcedony: a new testament for vanished evaporites: Journal of Sedimentary Petrology, v. 41, pp. 1045-1058.]
    [-- Lacroix, A. 1897, Le gypse de Paris et les mineraux qui l'accompagnent: Nouvelle. Arch. Mus. Hist. Nat., Paris, vol. 9, pp. 201-296.]
    [-- Salter, D. L. and West, I. M., 1965, Calciostrontianite in the basal Purbeck Beds of Durlston Head, Dorset: Mineralogical Magazine, vol. 35, p. 146-150.]
    [-- Shearman, D.J. and Fuller, J.G. 1969, Anhydrite diagenesis, calcitization and organic laminites, Winnipegosis Formation, Middle Devonian, Saskatchewan: Bulletin of Canadian Petroleum Geology, vol. 17, p. 496-525.]
    [-- West, I. M., 1964, Evaporite diagenesis in the Lower Purbeck Beds of Dorset: Proceedings of Yorkshire Geological Society, vol. 34, pp. 315-330.]
    [-- West, I.M. 1965. Macrocell structure and enterolithic veins in British Purbeck gypsum and anhydrite. Proceedings of the Yorkshire Geological Society, vol. 35, pp. 47-58.]
    [-- West, I.M., Brandon, A. and Smith, A. 1968. A tidal flat evaporitic facies in the Visean of Ireland. Journal of Sedimentary Petrology, vol. 38, pp. 1079-1093.]
    [-- Zaritsky, P. V., 1961, Celestite from the Lower Permian deposits of the Donbas: Doklady, vol. 133, pp. 801-804.]



    West, I.M. 1974. Evaporite diagenesis in the Lower Purbeck Beds of Dorset . Reprinted in Kirkland and Evans (Ed.): Marine Evaporites, Origin, Diagenesis and Geochemistry. Benchmark Papers in Geology. [See West, 1964] Abstract: Five stages have been determined in the diagenetic history of the calcium sulphate beds of Lower Purbeck age in Dorset, particularly by reference to abundant pseudomorphs and other relict textures and structures preserved in late-formed gypsum and in secondary silica and calcite. The weight of the overburden is thought to have controlled the changes. Occurrences are described of minerals, including celestite, calciostrontianite, lutecite and quartz remaining after the removal in solution of gypsum. A description is also given of secondary limestones which occur particularly in the Caps and Broken Beds. They are shown to be almost entirely replacements of original sulphate deposits.

    West, I.M. 1975. Evaporites and associated sediments of the basal Purbeck Group (Upper Jurassic) of Dorset. Proceedings of the Geologists' Association, London, 86, 205-225.

    Available online at:
    Paper - Evaporites and Associated Sediments of the Basal Purbeck Group (Upper Jurassic) of Dorset, by Ian M. West, 1975.

    Abstract: Four facies of limestones, each with particular contents of calcitised evaporites and of skeletal debris were recognised. They are compared with sediments of modern evaporite-depositing environments. The lowermost limestones, stromatolitic and pelletoid with foraminifera, probably originated in intertidal to shallow subtidal, moderately hypersaline, water. Overlying pelletoid limestones with algal-mats and some gypsum are products of high-intertidal flats. The main evaporite beds were originally gypsum, probably formed in supratidal to intertidal, very hypersaline, palaeoenvironments. The gypsum was converted to anhydrite and later brecciated in part, forming the Broken Beds. Extensive calcitisation produced porous unfossiliferous limestones. Ostracodal limestones above probably originated in shallow, only moderately hypersaline water. All the basal Purbeck strata were formed in and around a large shallow gulf with extensive tidal flats and with water of varying but predominantly high salinities. At times of uplift, thin soils developed on the former margins of the gulf. Forests were able to exist there because, although the area was within the semi-arid zone, it was probably very near to the boundary of the warm-temperate zone. End of Abstract. [Additional notes on topics discussed: Palaeosalinity origins of the basal Purbeck facies and lateral correlation. Mostly hypersaline to varying extents, including the stromatolite horizons. Fossil trees 'pickled' in a salt lake. Details of the basal Purbeck strata at all the main localities, studied petrographically. Depositional environments of the dirt beds and marls. Palaeoenvironmental significance of sedimentary cyles. Thickness variations of the facies. Relationship of the Broken Beds to the evaporitic facies. Local uplift. Penecontemporaneous fault movement. The Mupe Bay oil sand.] Some diagrams that are based on this paper are given below.
    Basal Purbeck logs Basal Purbeck logs Basal Purbeck Facies and Breccias

    West, I.M. 1979. Sedimentary Environments and Diagenesis of Purbeck Strata (Upper Jurassic - Lower Cretaceous) of Dorset, U.K. Unpublished Ph.D. Thesis, Southampton University, 181 p.
    Abstract: Twelve papers, notes and a contribution to a book, all either published or accepted for publication, constitute this thesis. All parts of the classic, shallow-water, schizohaline Purbeck Group of the type area are discussed but emphasis is on Lower Purbeck evaporites. Diagenesis of these involved much conversion of initial small lenticular crystals of gypsum to anhydrite with net-texture. The anhydrite was extensively replaced by calcite and celestite in the Broken Beds, a tectonic evaporite breccia at the base of the Purbecks. Evaporites were almost completely lost in solution from this breccia leaving characteristic relics of "vanished evaporites". Elsewhere, in the more argillaceous parts of the formation the sulphate remains, mainly as porphyrotopic secondary gypsum. Nodules and enterolithic veins are abundant in both the calcium sulphate and in the replacements. The similarity to those in Holocene sabkhas of the Trucial Coast (Shearman, 1966) suggested an origin on supratidal sabkhas, but there is a lack of desert sediments and instead the evaporites are interbedded with forest soils. Analogous Carboniferous evaporites show evidence of sabkha origins but no sign of desert conditions [West, Brandon and Smith, 1968. A tidal flat evaporitic facies in the Visean of Ireland. Journal of Sedimentary Petrology, 38, 1079-1093.]. New evidence has come from sabkhas in Northern Egypt where gypsum nodules develop in partly vegetated environment, dry but not excessively so, and supports other evidence for a semi-arid origin for the Lower Purbeck evaporites [West, Ali and Hilmy. 1979. Primary gypsum nodules in a modern sabkha on the Mediterranean coast of Egypt. Geology, 7, 354-358.]. The relatively dry climate was temporary and facies of higher parts of the Purbecks seem to result from sub-humid conditions. Throughout the formation lagoonal, 'intertidal' and supratidal deposits can be recognised but in the Middle and Upper Purbecks the lagoonal sediments have abundant brackish shelly faunas and, there, 'tidal-flat' deposits consist of shell-sand with dinosaur footprints but usually without evaporites. Progressively the proportion of land-derived clastics such as kaolinite and quartz sand increases as the continental Wealden is approached and final Purbeck sediments contain debris eroded from the underlying Portland Stone Formation, then uplifted at the western margin of the basin.

    West, I.M. 1979. Review of evaporite diagenesis in the Purbeck Group of southern England. Symposium on: West European Jurassic Sedimentation - "Sedimentation Jurassique W. European", A.S.F. (Association of French Sedimentologists), Special Publication No. 1, March 1979, pp. 407-416. In English with Abstracts in English and French.
    A general diagenetic classification of British Purbeck calcium sulphate rocks - gypsum and anhydrite Abstract (slightly enlarged and relating to fig 2, alongside): Evaporites and remains of "vanished evaporites" are widely distributed in the Purbeck Group of southern England. Associated sediments show that these were formed in semi-arid conditions on the extensive tidal-flats of a shallow hypersaline gulf. The primary sulphate was predominantly gypsum as lenticular crystals. Fabrics developed indicate five major stages of diagenesis. There was early recrystallisation of the initial gypsum mush (Stage I) of small lenticular crystals to a less porous anhedral fabric with the small-scale "net-texture" (Stage II), a microscopic network of impurities. The coarser nodular structure, chicken wire structure and enterolithic veins developed as the sulphate was converted to anhydrite (Stage III), a process which commenced penecontemporaneously and was completed before deep burial. The anhydrite was recrystallised so that several anhydrite fabrics now exist. Hydration is a relatively recent process resulting from contact with meteoric water near the surface after uplift and erosion had taken place. This usually commenced with a Stage IV of anhydrite containing gypsum porphyroblasts or porphyrotopes. The existing porphyroblastic or porphyrotopic gypsum represents the final Stage V. Concurrent with sulphate diagenesis there was replacement of the evaporites on an appreciable scale, particularly where they were not enclosed in impermeable clays. Calcitisation of the evaporites has produced peculiar, porous, secondary limestones and limestone breccias [resembling cargneule or rauhwacke]. Associated replacement products, including the strontium minerals - celestite and calciostrontianite, euhedral quartz, the varieties of chalcedony - lutecite and quartzine, suggest an inorganic mechanism for the calcitisation [but see also the thesis of Quest on isotopic studies of Purbeck strata which suggests that there was involvement of hydrocarbons in some cases.]. Criteria are listed that may be used for the recognition of similar replaced evaporites elsewhere. [End of abstract] There follows an extract (with minor additions):
    Evidence for Former Evaporites (Vanished Evaporites). An association of several points should be sought:
    1. Pseudomorphs of calcite, chalcedony or quartz (or moulds or casts) after gypsum, after anhydrite or after halite.
    2. Length-slow chalcedony (quartzine).
    3. Spherulites of the lutecite variety of chalcedony.
    4. Euhedral crystals of authigenic quartz.
    5. Celestite, sometimes with calciostrontianite (occasionally barytes or barite).
    6. Net-texture, a small-scale relic of gypsum with displaced impurities, now in secondary, sparry limestone, resulting from calcitisation.
    7. Chicken-wire, nodular structure or spherical vugs in limestone or dolomite.
    8. Coarsely crystalline (sparry) limestone, often porous, and without skeletal debris (possibly calcitised evaporites). May be massive, laminated or contorted.
    9. Small contortions that are not obviously of sub-aqueous slumping or other non-evaporitic origin.
    10. Minute rectangular relics of anhydrite in quartz or other minerals such as calcite (obvious in quartz because of contrasting moderate birefringence and the rectangular cleavage - but very small).
    11. Oligomict limestone breccia with a carbonate matrix (possible calcitised evaporite breccia).
    12. (an addition) A crumbly, brown, porous bed of carbonate and clay (like evaporitic cargneule or rauhwacke common in the Trias of the Alps and Pyrenees).
    ..Such evidence is likely to be found in other formations without normal marine faunas but with features such as microbial-mats, algal stromatolitic heads, caliches, abundant hypersaline ostracods or peculiar breccias. Obviously red-bed evaporites of more arid origin can provide additional criteria resulting from desert environments.


    West, I.M. 1988 Notes on some Purbeck sediments associated with the dinosaur footprints at Sunnydown Farm, near Langton Matravers, Dorset. Proceedings of Dorset Natural History and Archaeological Society, 109, 153-154.


    West, I. M. 1992. Contribution on Purbeck Group. - in: Cope, .J C.W., Ingham, J. K. and Rawson, P.F. (Editors). 1992. Atlas of Palaeogeography and Lithofacies. Geological Society of London. [With contributions from various authors. See Purbeck palaeogeographic maps - mid Portlandian (equivalent of Lower Purbeck) on page 129, and Berriasian (equivalent of Middle Purbeck etc) on p. 133].


    West, Ian. 2009. Geology of the Ridgeway Railway Cutting and Weymouth Relief Road. Webpage.

    Good fossil discoveries in the Black Band (83) and the Plant Bed (85) in the Middle Purbeck strata at an excavation at Bincombe, Weymouth Relief Road, Dorset

    Good exposures of the Purbeck Group, including the Cinder Bed, the Cherty Freshwater Member, the Upper and Lower Insect Beds etc. Illustrated with many photographs.


    West, I.M., Ali, Y.A. and Hilmy, M.E. 1979. Primary gypsum nodules in a modern coastal sabkha on the Mediterranean coast of Egypt. Geology, 7, 354-358. Abstract: Nodules of anhydrite in Holocene sabkhas of the Arabian Gulf and Baja California have been used as analogues to interpret calcium sulphate nodules in ancient rocks to be of sabkha origin. Nodules and incipient enterolithic veins of gypsum occur in a modern sabkha in Egypt about halfway between Alexandria and El Alamein, in a depression between a modern and a Pleistocene beach ridge. The displacive gypsum is apparently being precipitated from hypersaline calcium sulphate-saturated interstitial water that increases in salinity as it rises by capillarity from the water table to the surface. Calcium and sulphate ions seem to be derived mainly from dissolution of pre-existing lagoonal gypsum beneath the water table. The nodules occur within a supratidal sand unit of a sabkha sequence capped by a gray, saline soil on which grow clumps of halophytes, separated by salt-encrusted flats. This discovery shows that calcium sulphate nodules can develop (1) within sediments of a region where the climate is almost semiarid rather than very arid, (2) as primary gypsum rather than as anhydrite, and (3) as a consequence of redistribution of calcium sulphate. End of abstract. [The paper is not on the Purbeck Group but discusses some analogous evaporitic conditions.] Extract: "The Egyptian nodules demonstrate that extremely arid desert conditions are not essential for the formation of calcium sulphate nodules. Associations of nodules in sabkha sequences with halophytic plants and even trees [date palms receiving water from a ridge of ooid sand] may explain the proximity of evaporite nodules to petrified forests in ancient strata. "


    West, I.M., Anderson, F.W. and Faulkner, P.A., 1975. The Stone: Catalogue. In Platt . Excavations of Medieval Southampton. 304-314. [Some use of Purbeck stone].


    West, I.M., Ali, Y.A. and Hilmy, M.E. 1983. Facies associated with primary gypsum nodules of northern Egyptian sabkhas. Sixth International Symposium on Salt, 1983, vol. 1, Salt Institute, 171-183. Abstract: Modern sabkha and lagoonal, evaporitic environments are well-developed in the Mediterranean coastal zone of Egypt between Alexandria and El Alamein. It is a semi-arid region with an annual rainfall of about 19cm. Landward of the modern, ooid beach ridge is a narrow depression. This is occupied by partially vegetated sabkhas of desert loess and some small lagoons. Those which are moderately hypersaline contain the cockle [common edible, estuarine bivalve], Cardium glaucum; very hypersaline lagoons are precipitating gypsum. The sabkhas are usually underlain by the following sequence of Holocene sediments. At the base are lagoonal shelly silts, locally with Cardium. Lagoonal gypsum follows. Then comes desert-loess, within which gypsum nodules are developing by precipitation from capillary water. These sabkha deposits are being gradually covered by ooid sand. The present marine transgression should ultimately produce a sequence in which an oolitic limestone is overlain by a cockle bed, followed by laminated gypsum, overlain, in turn, by a red bed siltstone with gypsum nodules. This would be capped by oolitic limestone. Ancient strata resembling certain of these facies include cockle beds associated with evaporites in the British late-Jurassic [or early Cretaceous, Purbeck] strata. The facies association of desert loess with gypsum nodules, halite, caliche, palygorskite and scorpions can be matched in the British Trias. End of Abstract.
    [The paper is partly concerned with Purbeck analogues in northern Egypt.] Extracts on analogue for the Purbeck cockle beds, such as parts of the Hard Cockle Member and Soft Cockle Member with the ancient "cockle"Protocardia purbeckensis:
    Cockle shells on a dried saline lagoon of northern Egypt
    "A modern, moderately hypersaline environment with Cardium glaucum is a lagoon (AL.1) east of El Alamein [ The Second World War battlefield]. The brine is of approximately 55% salinity in summer. There are other similar lagoons nearby. The bivalves here are dwarfed (Figure 4), with a mean length of 12.6mm, and are associated with turreted gastropods. Elsewhere, Cardium glaucum occurs in hypersaline lagoons of the south of France and of the Sea of Azov (Rygg, 1970). The abundant Fragum (Cardiaceae) fo hypersaline Shark Bay, Western Australia (Hagan and Logan, 1974) may be analogous. ... Perhaps the best known examples of ancient "cockle beds" with evaporites are in the lagoonal Lower Purbeck Group (Upper Jurassic-Lower Cretaceous) of southern England (Arkell, 1947). The "cockles" are bivalves of the species Protocardia purbeckensis (Figure. 4). They occur in members known as the "Hard Cockle Beds" and the overlying "Soft Cockle Beds" (Bristow and Forbes in Damon, 1884; Clements, 1969; Ali, 1981). In the Soft Cockle Member there is secondary gypsum that has replaced anhydrite, which in turn is a replacement of primary gypsum (West, 1964). It contains well-developed nodules and enterolithic veins (West, 1965). Calcitized gypsum occurs in the Hard Cockle Member. The usual association of the small cockle Protocardia purbeckensis with evaporites suggests that the species was tolerant of hypersaline conditions. Comparison with modern analogues suggests that it might have been able to live in brine of up to about 60 parts per thousand salinity. The lack of desert sediments, the presence of coniferous forests and the characters of the insect, molluscan and ostracod faunas is evidence, however, for a climate that was semi-arid and Mediterranean type (West, 1975; 1979; Francis, 1983). This is confirmed by the palaeolatitude of about 37 degrees N. (Smith and Briden, 1977)....."

    West I.M. and El-Shahat, A. 1985. Dinosaur footprints and early cementation of Purbeck bivalve beds. Proceedings of Dorset Natural History and Archaeological Society, 106, 169-170.


    West, I.M. and Hooper, M.J. 1969. Detrital Portland chert and limestone in the Upper Purbeck Beds [i.e. Durlston Formation of the Purbeck Group] at Friar Waddon, Dorset. Geological Magazine, 106, pp. 277-280. By Ian West and Malcolm Hooper.
    [This paper is relevant to date of Portland diagenesis because the conclusions are of erosion in the Weymouth region in Late Cimmeran times (although the Inversion structure was not understood at that date). over the Weymouth Anticline. The date of origin of the Weymouth Anticline is important, though. Was it really present in incipient form by the Aptian, or has the detritus been derived from the north. In other words are current Inversion Tectonic theories, involving Tertiary origin for the Weymouth Anticline, correct for this area? Or is the Anticline of earlier origin. It is possible to follow up this topic. This short paper poses a question, even in the year 2015!]
    Abstract and some of the text is given below.
    [Dr. Ian West, university geologist. Malcolm Hooper, now a geological mining consultant]
    Abstract: Pebbles of derived Portland chert and limestone have been found in the Upper Purbeck Beds [now Dulston Formation of the Purbeck Group] at Friar Waddon, Dorset [just west of Upwey and north of Weymouth]. The Unio Bed at this locality is of unusual lithology and with derived phosphatic fossils and with fish teeth. The presence of this chert in the Upper Purbeck Beds [Durlston Formation] and its apparent absence in the Lower Purbeck [Lulworth Formation] pebble beds suggest that a [the?] major phase of silicification in the in the Portland Stone [Formation, late Jurassic] took place at about Middle Purbeck times [probably correct]. Furthermore erosion of the Portland Beds occurred in the Weymouth region, probably on the crest of the Weymouth Anticline during Upper Purbeck times [Berriasian].
    [Update - re Inversion Tectonics, October 2015 - imw. It is possible that derived materal was the result of early, local erosion that occurred on or adjacent to the north side of the Abbotsbury Fault because of Late Cimmerian uplift. The location is on the south side of the boundary of the Weymouth area inversion (separated from the main inversion, further west by the well-known relay ramp. Thus, there was early upthrow to the north. cf. the Weald Basin Inversion. On a much smaller scale it is probably evidence of a small analogue of the the famous Perce Allen - type of transport in the Weald where clastics from a northern "high" were trasported into the Weald Basin, prior to the tectonic inversion. In 1969 it was not viewed in terms of Inversion Tectonics. Subsequent finds of land-derived material, including cones and seeds, at Portesham in the Portesham Charophyte Chert nearby support this later theory. However, there are problems in applying this theory. See the details and the discussion below, and bear in mind the occurrence of the "Portland Screw" gastropod - Aptyxiella. This is a complication]
    Text of West and Hooper, 1969:
    "It is rarely possible to establish accurately the date of formation of chert in limestones. On petrographic evidence a diagenetic sequence involving silica has been suggested for the Portland Beds by Wilson (1966) and for the Lower Purbeck Beds [Lulworth Formation] by West (1964)[Evaporite diagenesis in the Lower Purbeck Beds of Dorset. Proc. Yorks. geol. Soc., 34, 315-330.]. Both suggested that an appreciable proportion of replacement by silica occurred at an early stage. A small excavation in the Upper Purbeck Beds [Durlston Formation] near Upwey, Dorset has recently revealed pebbles of derived chert in Purbeck sandstone and these indicate the date of origin of the chert.
    The old overgrown excavations or quarries (map reference 644857), in which the unusual blocks of Upper Purbeck Unio Bed were found, lie about 100 metres to the west of Friar Waddon Farm. On the same line of strike, he Unio Bed was reported to have been seen in situ in the roadway just west of the farm by Wilson et al. (1958) and it can also be found in situ in the farmyard. These exposures are the most westerly of this horizon in Dorset. They lie jus south of a small exposure of problematical unfossiliferous sand that has been regarded as either basal Wealden Beds or decalcified Upper Purbeck Beds (Wilson et al. 1958).
    2. The Unio Bed.
    At Friar Waddon the Unio Bed is a hard, calcite-cemented sandstone but, in contents of Unio, Viviparus, fish teeth and reptilean bones, it resembles the equivalent limestone in the Isle of Purbeck. At both localities there is the unusual feature of glauconite present in an apparently freshwater bed, although the mineral is less abundant at Friar Waddon [added note - there is also oil in the bed at Stair Hole, Lulworth Cove]. The pebbles of limestone and chert with phosphatic nodules and derived fossils at the western locality, suggest that the bed marks a minor unconformity. It may perhaps indicate an appreciabe break in sedimentation that shortly preceded the change to a Wealden facies.
    Fisher in 1856 observed that the Purbeck Beds of Dorset become more arenaceous westwards and in that direction contain more of the spoils of land. In the basal Purbeck Beds the evaporitic strata of east Dorset are interdigitated in the west with freshwater horizons (West, 1961). The pebbly and sandy nature of the Upper Purbeck Beds [Durlston Formation - part] at Friar Waddon are in accordance with the general westward facies change and the proximity of land to the west.
    The brown and black phosphatic nodules of the Unio Bed are isotropic in thin-section. Phosphatic rolled fossils were submitted to Dr. Casey who kindly examined them. He found (personal communication, 1964) indeterminate perisphinctacean ammonites, ?Protocardia juv., ?Anisocardia juv. ?Eodonax juv. and the remains of a gastropod and a serpulid. He commented that the black phosphatic material reminded him of debris from the Upper Jurassic Lydite Beds in which the ammonite Pavlovia abounds.
    The samples from the Unio Bed contain numerous fish teeth. Dr. Patterson who examined these, reported (personal communication, 1964) indeterminate perisphinctacean ammonites [noe added: i.e. like say the well-known Pavlovia rotunda of the Upper Kimmeridge Clay of Chapman's Pool, but not necessarily that species], ?Protocardia juv. ?Anisocardia juv. ?Eodonax juv. and the remains of a gastropod and a serpulid. He commented that the black phosphatic material reminded him of debris from the Upper Jurassic Lydite Beds in which the ammonite Pavlovia abounds. [note added. In modern terms that this is the type of reworked debris that is present at or near the Late Cimmerian Unconformity, under the Gault and UGS in the Isle of Wight, imw 29th Nov. 2015.]
    The samples from the Unio Bed contain numerous fish teeth. Dr. Patterson who examined these, reported (personal communication, 1964)the presence of Hybodus sp., Lepidotes sp., Caturus tenuidens Smith Woodward, Coelodus mantelli Agassiz and other indeterminate fish teeth and scales.
    Patterson (1966) has since described a new species present at this horizon - Lonchiodon heterodon Patterson. Teeth of crocodiles are associated with the fish teeth [fossil crocodile remains are common in the Durlston Formation of the Purbeck Group, as at Durlston Bay, Swanage.]
    Particle size analysis of the dilute acetic acid insoluble residue was undertaken. The residue included the chert pebbles, the reworked phosphatic material, the quartz sand and other clastic components. A bimodal distribution was observed with modes in the 2 to 3 (?) size range (fine sand) and the -5 to -4 (?) range (pebbles).
    Petrography of the Pebbles [heading]
    Most of the pebbles consist of cream coloured limestone or a weathered chert with some content of calcite. The limestone is an intramicrite (terminology of Folk, 1959 [ i.e. - with intraclasts in a micrite matrix - i.e. a carbonate breccia] of coarser grain size than any seen in the Purbeck Beds. Quartz sand is usually rare but there are fragments of thick-shelled bivalves and remains of echinoderms [both more Portland features than Purbeck]. Original siliceous spicules of Pachastrella and Rhaxella have been replaced by calcite. This phenomenon was reported by Wilson (1966) who found it in the Corallian and the Portland Beds but only associated with chert in the latter [normally abundant in the Portland Chert Member]. On independent evidence he regarded this calcitisation as an early stage of diagenesis. It is a common feature of the Portland Stone wherever micrite constitutes and appreciable portion of the rock.
    The pebbles of chert consist of incompletely silicified intramicrite of similar petrography to the limestones and, significantly, with turreted gastropods [i.e Aptyxiella, well-known in the Portland Roach, but generally confined to the Isle of Portland. However, see below - there is a difference from Portland regarding the detritus]. An origin in the Portland Beds seems certain.
    The thin-sections of the limestone and chert pebbles were compared to about fifty thin-sections of limestone and chert from the Portland Stone of various localities in Dorset. the pebbles resemble many specimens from the Portland Freestone of the Isle of Portland. There the high content of ooliths and the general lack of micrite is characteristic. It has not been possible to find exact comparisons. [note that the Portland Stone in the Upwey region is of a rather "chalky" facies and not in general a good oolite - see details of the Weymouth Relief Road excavation.]
    The Friar Waddon Unio Bed demonstrates that erosion of the Portland Beds occurred in Purbeck times. The limestone pebbles suggest that the material was transported only a short distance because the calcium carbonate was not removed in solution. The presence of a turreted gastropod in chert suggests comparison with the chert containing Aptyxiella portlandica which is almost confined to the Roach at the Portland Freestone at the north end of the Isle of Portland [but Aptyxiella also occurs in the Vale of Wardour and in the old Swindon Town Gardens Quarry]. Pebbles of similar chert are present at the unconformity at the base of the Gault at Osmington ( Arkell, 1947). At the neighbouring locality of Holworth House, Ringstead, only a few kilometres from Portland the condensed rotunda sequence of the [Upper] Kimmeridge Clay resembles the Upper Lydite Bed (, Arkell, 1947, Casey 1967). Erosion of the former could have provided the derived phosphatic material.
    The above evidence suggests that the material was eroded from an area that was probably near Friar Waddon near the north end of the Isle of Portland and near Ringstead [all in the Relay Ramp region]. Early erosion over the crest of the Weymouth Anticline would accord with this.
    [Later comment by imw, 2015. However, note (2015) that the uplift of the Weymouth Anticline may not have happened so early, i.e. in the Late Cimmerian phase. The Weymouth Anticline is more likely to be due to the second phase of tectonics, that of the Tertiary compression folding, i.e. the later Inversion. This was not understood in 1969 when the paper was written.]
    [continues]. It would account for the presence in the pebbles of features typical of both the Isle of Portland and of the Dorset mainland. Erosion probably penetrated down to the uppermost part of the Kimmeridge Clay at the centre of the anticline. Later, further uplift and erosion took place before deposition of the Gault.
    The chert pebbles permit a date to be established for the major phase of silicification in the Portland Beds [Portland Stone Formation]. A careful examination was made to search for any signs of silicification occurring in situ in the Unio Bed. None was found and it clear that the pebbles were of chert before their emplacement in the Upper Purbeck Beds [Durlston Formation of the Purbeck Group]. No pebbles of Portland chert were found in the Lower Purbeck dirt beds, only authigenic nodules usually associated with the original presence of evaporites [silicification of evaporites is common in the Lulworth Formation of the Purbeck Group]. Nearly forty thin-sections of pebbles from the Great Dirt Bed of Portland and of Lulworth revealed no Portland chert, only a little silicification of microscopic dimensions in pebbles of Purbeck limestone. It would be surprising if none of the resistant Portland chert was found in any of these lower Purbeck [Lulworth Formation] pebble beds, had it existed at the time of their formation. Blake (1880) referred to some detrital Purbeck chert in a Purbeck dirt bed on Portland but this could not be confirmed and he may, in fact, have observed Purbeck authigenous silica.
    Thus the major phaseof chert formation in the Portland Beds apparently took place between the deposition of the Lower Purbeck Caps and the Upper Purbeck Beds. Wilson's (1966) suggestion of two stages of silica diagenesis in the Portland Beds is supported by the presence of brecciated chert of the Chert Vein at St. Alban's [or St. Aldhelm's] Head, enclosed in a later chert matrix, and by other field evidence. It is now possible to confirm independently the early date of the major phase of silicification.
    Acknowledgements. The authors are obliged to Dr. R. Casey and Dr. C. Patterson for the identification of faunal remains. They are most grateful to Professor F. Hodson [the late Professor F. Hodson] for advice and encouragement.
    References: [not given here. Ten references, probably all or almost all, already present within the present bibliography website and so repeated here.][end of paper]


    West, I.M., Shearman, D.J. and Pugh, M.E. 1969. Whitsun Field Meeting in the Weymouth Area, 1966. Proceedings of the Geologists' Association, 80, 331-340. [Portland, section of Perryfield Quarry etc]


    Westhead , R.K. and Mather, A.E. 1996. An updated lithostratigraphy for the Purbeck Limestone Group in the Dorset type area. Proceedings of the Geologists' Association, London, 107, 117-128.
    Weston, C.H. 1849. Further Observations on the Geology of Ridgway near Weymouth. Proceedings of the Geological Society in: Quarterly Journal of the Geological Society; 1849; vol. 5; issue.1-2; p. 317-319. By Charles H. Weston, B.A., F.G.S.
    In his former paper on this subject Mr. Weston endeavoured to show the existence of the Hastings sand at Ridgway. He has since visited the various sections of the Wealden between Hastings and Lulworth, and then re-examined the railway cutting at Ridgway, and the result has been to confirm his former views. He finds that the variegated clays, loams and sands exhibited in the latter locality are by no means local, but occur also in Kent, in the south of Sussex, in the Isle of Wight and in Dorset; and he has recently observed them on the Brighton and London Railway near Balcombe. In Sussex these variegated clays form a very subordinate part of the formation, but are more developed in the counties to the west.
    In his concise but masterly Geological Sketch of the Vicinity of Hastings, Dr. Fitton notices the "greenish and purplish variegated clay" and sand visible at Leaness Point, between Hastings and Winchelsea. They lie beneath a stratum which Mr. Webster describes as a sandstone intersected by numerous veins of argillaceous iron ore, and rest on a dark-coloured shale also containing several layers of rich iron ore, formerly much worked in Sussex. These lowest shales are placed by Dr. Mantell in the upper part of the Ashburnham beds. Dr. Fitton also points out the anticlinal axis passing from the shore near Leaness through the highest point of Fairlight Down to Battle, the strata dipping away from it on both sides.
    Mr. Weston has himself found similar ferruginous and variegated clays and sands in a hill beyond Ham Street on the Rye and Ashford Railway, and near Hastings at Bopeep, west of St. Leonard's, and at Bexhill. He next found them at Sandown Bay in the Isle of Wight, and also between Atherfield and Afton Downs. The clays contain no fossils but the Cypris valdensis and Paludina in some associated beds.
    The next appearance of the Hastings sand is at Swanage Bay in Dorset, emerging from under the very steep escarpment of Ballard Downs. The entire group was in this place more varied, and consisted of a greater number of alternations of sands and clays than I found in the Isle of Wight. It appeared in consequence to combine in miniature the more extensively-developed arenaceous deposits of Hastings and the almost exclusive argillaceous strata of the southwest coast of the Isle of Wight.
    The variegated clays are indentical with those of the latter and of Ridgway. I could however discover no fossils in them.
    The Chalk Downs (of which Ballard Down forms the southeastern extremity) run across the Isle of Purbeck and terminate in the fine bluff cliff of Purbeck Hill on the east of Lulworth. The sections below Purbeck Hill are those of Worbarrow Bay on the east of the chalk and Mewp Bay on the west, of which I only visited the former.
    The Hastings sands of Worbarrow Bay consist of a considerable admixture of clays and sandstones. The latter appear to abound here more than at Swanage Bay. The clays posses the peculiar character and colours of those at Ridgway, but some of their colours are rather more vivid. The colour of the sandstones, from the great abudance of the ferruginous base, is in many places intense. I could not discover any organized remains in these clays. I think no one who has examined this part of Dorset, and has traced the base of the chalk escarpment from Ballard Down to Purbeck Hill, can fail to be convinced of the correctness of Dr. Fitton's view, and to feel satisfied of the continuity of the Wealden formation right across the peninsula of Purbeck.
    He next visited Lulworth Cove, where the general appearance of the Hastings sand is similar to the localities we have already described. Not far from this place is the last coast exhibition of the Wealden formation in Man-of-War and Durdle Coves. These are separated from each other by a short isthmus, which has been protected by a rock of greatly-inclined strata of Purbeck stone, and is composed of the Wealden very condensely and vertically developed. From this isthmus we see the eastern side of Man-of-War Cove, which appeared evidently to consist of Hastings sand. That point and the isthmus are clearly the remnants of a once continuous mass. The west side of Durdle Cove is composed of chalk which here abuts upon the sea, and runs uninterruptedly along the coast to the high point of White Nore, whence it trends inland.
    In all these sections the variegated clays, loams and sands were identical in character with the Ridgway deposit. In this section, which he visited the following day, Mr. Weston "traced the Purbeck beds to their first uninterrupted termination, which consisted of calc grit with Purbeck fossils. Beyond this were clays, and then alternations of the calc grit and clays, and ultimately the Hastings bed exclusively. This section therefore exhibits the same features which Dr. Fitton has observed respecting other sections of the Wealden, showing, 1st, the continuity and sequence in the deposition; and 2ndly, the quiet process of such deposition. Hence we have the most satisfactory evidence that the beds overlying the Purbeck followed in regular succession, and were in fact rather a continuation of them.
    On the whole Mr. Weston concludes not only that the variegated clays of Ridgway Hill really belong to the Hastings sand formation, but that their geognostic position is in the lowest part of the Worth and Tilgate group, separating it from the inferior Ashburnham beds.
    Mr. Weston also mentions that he found the Purbeck deposits to extend as far west as the end of the Corton Range, and therefore spreading co-extensively with the Portland oolite to the vicinity of Portisham.
    In regard to the attempt to explain the singular interposition of the Oxford clay between the Wealden and the cretaceous series as resulting from a drift, he remarks:-
    "1st. That I could not perceive in the fossils those marks of abrasion which would indicate their having been drifted.
    2ndly. That the Oxford clay has considerable depth. It has already been penetrated to the depth of about sixty feet without reaching its termination.
    3rdly. That the vertical surface of the wall of chalk is hardly consistent with the natural results of previous diluvial action in that locality. And,
    4thly. In many places the theory of a drift may involve no physical difficulties. But at Ridgway this idea would involve serious objections. Whence, it might be asked, could the Oxford clay have been drifted? The Oxford clay of Ridgway is about 200 feet above that of Weymouth; and the next exhibition of that bed on a higher level would be at Little Bredy near Abbotsbury Common, at a distance of between five and six miles, and at a level, I apprehend, certainly far below that of Ridgway. Whatever difficulties may therefore be supposed to attach to the theory which I have ventured to propose, will not, I think, be diminished by the suggested explication of a drift. I have also satisfied myself by repeated and careful examination that the section contains no double fault.
    Westwood , J.O. 1854. Contributions to fossil entomology. Proceedings of the Geological Society, in: Quarterly Journal of the Geological Society, 1854, vol. 10, issue 1-2, pp. 378-396. Plates 14 to 18. By J. O. Westwood, F.L.S. etc. Available online from the Lyell Collection, Geological Society of London.
    The microscopical examination which I have been compelled to make of so many hundreds of fossil insect-remains, for the most part in a fragmentary condition, from the Lower Purbecks of Dorset, although beyond measure tedious from the unsatisfactory results afforded by the nature of the specimens, has still enabled me to arrive at some results, and to form a general comparison of these insect-deposits with those which I similarly investigated whilst preparing the plates of Mr. P. B. Brodie's work on the fossil insects of the Wiltshire Purbecks, etc. If we take into consideration the small, and even minute size of the great majority of the insects, and indeed of the whole of the Coleoptera, which have been passed under review, the idea, that we have before us the wreck of an Insect Fauna of a temperate region, is at once raised; for although it would be rash to assert that a mass of remains of the existing tropical insects might not be accumulated in which a large quantity of minute beetles and flies would not be present, yet I cannot conceive any process, either arising from currents of water, or chemical dissolution of insect matter, which would carry off or destroy the many gigantic forms of insect life always occurring in the tropics.
    Whitaker , W. and Edwards, W. 1926. Wells and Springs of Dorset. Memoir of the Geological Survey of England and Wales. [This includes the log of the Friar Waddon Borehole, Dorset with Purbeck strata logged but not described in detail. The Friar Waddon Borehole log is relevant to the Purbeck sections at Upwey, Fisher's log of the Ridgeway (or Ridgway) Railway Cutting and in the Weymouth Relief Road.]
    Wilding , R. 1988. Osmond Fisher (1817-1914), Dorset geologist and pioneer geophysicist. Proceedings of the Dorset Natural History and Archaeological Society, 110, 17-22. (See Fisher, 1856, On the Purbeck strata of Dorsetshire). [Summary - Osmond Fisher was born in Osmington in 1817. He was interested in geology from a very young age. He graduated in mathematics at Jesus College, Cambridge in 1841, then took holy orders, and in 1845 was appointed Curate-in-charge of the newly rebuilt All Saints' Church, Dorchester, where he stayed for eight years. While at Dorchester he made some useful observations on the geology of Dorset. Later he began to use his mathematical knowledge to solve some geological problems. His book - Physics of the Earth's Crust (1881) was the first textbook of geophysics; in this he anticipated many of the ideas that are now part of plate tectonics theory. For 39 years he was rector of Harlton, near Cambridge, but he returned to Dorset as often as he could to study and write about its geology. He died in 1914 in his 97th year. He was still publishing whe he was 96! ]
    Wilkinson, I.P. 2007. The distribution of Late Kimmeridgian and Portlandian ostracoda in southern England. La repartition des ostracodes du Kimmeridgien superieur au Portlandien en Angleterre meridionale Revue de Micropaleontologie. By Ian P. Wilkinson, British Geological Survey, Keyworth, Available online 1 October 2007.
    Abstract: The vertical distribution of ostracods in the Upper Kimmeridgian and Portlandian (sensu anglico) succession in three cored boreholes at Hartwell, Tisbury and Fairlight, are compared to other successions in southern England. The Upper Kimmeridge Clay Formation yields rich, but low diversity ostracod faunas, characterised by stratigraphically restricted species of Aaleniella, Galliaecytheridea, Klentnicella, Macrodentina, Mandelstamia, Micrommatocythere, Paralesleya and Prohutsonia. Several continue into the Portlandian, but some species, belonging to genera such as Cytherelloidea, Paracypris, Fabanella, Galliaecytheridea, Klieana, Paraschuleridea, Eocytheridea, Paranotacythere, Procytheropteron, Rectocythere and Macrodentina, appear for the first time. Biostratigraphical subdivision is made difficult by provincialism caused by decreasing salinities and facies change during the Late Portlandian. Marine taxa such as Protocythere, Macrocypris, Paraschuleridea, Paranotacythere, Procytheropteron and Rectocythere were replaced by euryhaline forms, such as species of Fabanella and Mantelliana, and fresh-oligohaline species of the genera Cypridea, Scabriculocypris, Alicenula and Rhinocypris.
    Will , J. 2003. The Sedimentology and Palaeoenvironments of the Purbeck Group of the West Coast of Portland. 42pp. Unpublished B.Sc. undergraduate research project, 2002-2003, School of Ocean and Earth Science, Southampton University. Abstract: There is a succession of Late Jurassic/Early Cretaceous lagoonal strata present on the west coast of the Isle of Portland. There is a transition upwards from low to high salinity. There are palaeosols indicating shallower conditions in places, allowing ancient soils to form. There are two evaporite beds present, which contain lutecite, which is an indicator of evaporites. High energy is indicated by ripple laminations in some limestone beds and coarser particle size in the Hard Slatt. The gypsum discovered is secondary gypsum in the upper evaporite beds and good pseudomorphs after halite are present in the upper limestone beds. The section is an example of hypersaline lagoon conditions which in this region marked the regression at the end of the Jurassic Period. [Report by Jennifer Will on her student project. One copy filed at Southampton University.]
    Willett , E.W., 1881. Notes on a mammalian jaw from the Purbeck Beds at Swanage, Dorset. By Edgar W. Willett, B.A. With an Introduction by Henry Willet, Esq. F.G.S. (read May 25, 1881). Quarterly Journal of the Geological Society, London, 37, 376-380. [He found mammal remains in the Upper Dirt Bed or Fern Bed in a pit on the cliff top - Willett's Mammal Pit.]
    Williams , D.F. 2002. Purbeck marble in Roman and medieval Britain. pp. 126-131. In: Hinton, D.A. 2002. Purbeck Papers. [On archaeology of the Isle of Purbeck, not on the Purbeck Group; however with much reference to Purbeck Marble etc.] University of Southampton, Department of Archaeology, Monograph No. 4., Oxbow Books, 144pp. Edited by David A. Hinton.
    Abstract: Purbeck marble was exploited almost immediately after the Roman conquest, principally for architectural veneers and floors, where it was often combined with other marbles. It was also used for a few sculptures, and for portable items such as mortars. In the Middle Ages there was a wider range of products, including funeral monuments, columns and carved capitals, but also again sometimes in combination with other marbles.
    This paper contains useful information of Purbeck marble at Colchester, Fishbourne, London, Canterbury and Lincoln by the Romans. There is also interesting information on its use in medieval Britain [see also Drury (1984), The use of Purbeck marble in mediaeval times.]
    Unfortunately, the short geological section at the beginning of this paper contains significant errors. Fig. 4.1 is a map of the Isle of Purbeck that is wrong (compare the map with that of the British Geological Survey - Swanage Sheet, 343 or even the old map in Robert Damon (1884)). It includes "Great and inferior oolite groups" and it shows an incorrect and excessively large outcrop of the Purbeck Marble. There are lesser problems with the text, but note that this well-known biomicrite is actually Cretaceous (Berriasian), not Jurassic, as stated in the paper. There are also minor errors in the names of the gastropods, and at least one of these mistakes will be obvious to the reader.
    After this the paper enters into archaeology, its main purpose, and contains much interesting and valuable information on the former use of Purbeck marble. It has a useful reference list.
    Williamson I.P. 2008. The distribution of Late Kimmeridgian and Portlandian ostracoda in southern England. (La repartition des ostracodes du Kimmeridgien supérieur au Portlandien en Angleterre meridionale). Revue de Micropaleontologie, vol. 45, Issue 3, July - September 2008, pp. 221-238. Ostracodology - Linking bio and geo sciences in the marine realm - Part 1. By Ian P. Wilkinson, British Geological Survey, Keyworth, Nottingham, NG12 5GG. Available online from 1 October 2007.
    The vertical distribution of ostracods in the Upper Kimmeridgian and Portlandian (sensu anglico) succession in three cored boreholes at Hartwell, Tisbury and Fairlight, are compared to other successions in southern England. The Upper Kimmeridge Clay Formation yields rich, but low diversity ostracod faunas, characterised by stratigraphically restricted species of Aaleniella, Galliaecytheridea, Klentnicella, Macrodentina, Mandelstamia, Micrommatocythere, Paralesleya and Prohutsonia. Several continue into the Portlandian, but some species, belonging to genera such as Cytherelloidea, Paracypris, Fabanella, Galliaecytheridea, Klieana, Paraschuleridea, Eocytheridea, Paranotacythere, Procytheropteron, Rectocythere and Macrodentina, appear for the first time. Biostratigraphical subdivision is made difficult by provincialism caused by decreasing salinities and facies change during the Late Portlandian. Marine taxa such as Protocythere, Macrocypris, Paraschuleridea, Paranotacythere, Procytheropteron and Rectocythere were replaced by euryhaline forms, such as species of Fabanella and Mantelliana, and fresh-oligohaline species of the genera Cypridea, Scabriculocypris, Alicenula and Rhinocypris.
    Wilson , R.C.L. , West, I.M. and Sellwood, B.W., 1983. Post-Congress Geological Tour D - Dorset. 11th World Petroleum Jubilee Congress, 58 pp.

    Wilson, V. , Welch, F. B. A., Robbie, J. A. and Green, G.W. 1958. Geology of the Country around Bridport and Yeovil. Memoir of the Geological Survey of Great Britain, Explanation of sheets 327 and 312. 118-129. With contributions on: The Purbeck Beds by F.W. Anderson, D.Sc.; Palaeontology by R.V. Melville, M.Sc.; and Ground Water by S. Buchan, B.Sc., Ph.D. [See particularly pp. 118 et seq - Purbeck Beds [by F.W. Anderson. Purbeck ostracod zones of that date are given with thicknesses of lithological subdivisions.].
    Wimbledon, W.A. 1976. The Portland Beds of Wiltshire. Wiltshire Archaeological and Natural History Magazine, 71, pp. 3-11.

    Wimbledon, W.A. 1987. Rhythmic sedimentation in the Late Jurassic-Early Cretaceous. Proceedings of the Dorset Natural History and Archaeological Society, 108 for 1986, 127-133. Most of this paper is on the Portland Group. An Appendix refers to Purbeck nomenclature. Abstract: A number of shallowing and deepening phases is described in the late Kimmeridgian - Berriasian interval. Eleven deepening / transgressive events are noted in the most complete Dorset section. A preferred lithostratigraphy for these beds is compared to previous lithostratigraphy, and "event correlations" are critically examined.

    Wimbledon, W.A. and Cope, J.C.W. 1978. The ammonite faunas of the English Portland Beds and the zones of the Portlandian Stage. Journal of the Geological Society, London 135, 183-190.
    Abstract: On the basis of new and large collections of ammonites, a succession of ammonite faunas is described from the Portland Beds of southern England and a revised scheme of Standard Zones (=chronozones) proposed. The faunas of the Portland Freestone of Dorset are shown to consist largely of hitherto undescribed species; Titanites anguiformis sp. novo is described and figured therefrom. Correlations are proposed with other areas where the Portland Beds occur, and the scheme is integrated with the zonal scheme proposed by Casey (1974) for the younger Portlandian faunas. Glaucolithites glaucolithus Buckman and Titanites giganteus (Sowerby) are redefined with the aid of new material. 'Portlandian' is preferred as stage name for the terminal Jurassic stage. [end of abstract]

    Example extract:
    The first scheme of zones for the Portlandian Stage of the Upper Jurassic was proposed by Salfeld (1913) but has suffered because some of the index species used were of dubious interpretation, and it was based on sections in the S Midlands now known to be incomplete. Salfeld's zonal table was succeeded by Buckman's hemeral scheme. Buckman was the first person to attempt any really detailed stratigraphical work on the Portland Beds, and he obtained, from quarries in the Thame district ammonites which were described half a century ago in 'Type Ammonites' under a multiplicity of new generic and specific names. Although Buckman's hemeral scheme has long since been abandoned, his work is a very useful record of the faunal succession in an area where there are now few exposures. Comparison with sections further south has shown that his records are essentially correct as far as recording of horizons is concerned. Where his work failed, and also that of subsequent workers, was in the correlation of the south Midland successions with those of the Dorset coast. This was due to the persistent acceptance of certain widespread misconceptions concerning the ammonites and their stratigraphic relationships, a lack of systematic collecting, and a consequent inability to establish the ranges of the faunal assemblages.
    Recent work on the Portland Beds throughout their outcrop by the authors, but with emphasis on the presumed complete successions in Dorset, has shown how wrong some of the former correlations were, and although work has not yet reached completion (when a joint monogtaphic work is contemplated) sufficient is now known to set up a revised zonal scheme.
    The work on the faunas of the Portland Stone, the subjacent rocks north of Dorset, and the systematic palaeontology, is by Wimbledon. This has been integrated with Cope's work on the Portland Sand in Dorset.
    The Faunal succession
    A succession of distinctive ammonite faunas has been recognised throughout the Portland Beds (Fig. 1). In ascending stratigraphical order these are:
    Fauna 1: Progalbanites-Epivirgatites fauna
    The genus Progalbanites Spath 1933 appears to be quite distinct from the earlier Volgian genus Zaraiskites with which it has long been confused (see Casey 1967, p. 132). The type species of the genus, P. albani, is frequently common, and is associated with hitherto undescribed species of the genus. The remainder of the ammonite fauna includes species of Epivirgatites including E. nikitini (Mich.), E. vulgaris (Spath) and others. There are also undescribed species of Pavlovia. Amongst the pavloviids are occasional fragments of forms apparently close to the subgenus Epipallasiceras Spath (see Buckman 1926, pI. 693). [continues for 10 pages, including three large photographic plates of ammonites.

    Wimbledon, W.A., Allen, P., Parker, A., Ogg, J., Algeo, T., Hunt, C.O. and Nunn, J. in preparation 1997. The Kimmeridge-Wealden transition in the Portland, Lulworth and Swanage districts; the Portland-Purbeck type sections - their stratigraphy, palynology, clay mineralogy, heavy minerals and palaeomagnetism.

    Wimbledon, W.A. and Hunt, C.O. 1983. The Portland - Purbeck junction (Portlandian - Berriasian) in the Weald, and the correlation of latest Jurassic - early Cretaceous rocks in southern England. Geological Magazine, 120, 267-280.
    Wolburg, J. 1959. Die Cyprideen der NW-deutschen Wealden. [The Cypridean ostracods of the northwest German Wealden]. Senckenbergian Lethaea, [an international journal of Palaeontology and Stratigraphy, published by the Senckenberg Nature Research Society, Frankfurt am Main, Germany.] Relevant to Purbeck Cypridea ostracods etc.
    Woods, M.A.. 2009 Weymouth Relief Road : Temporary Excavations in Jurassic and Cretaceous strata (May 2009). Nottingham, UK, British Geological Survey, 17pp. (OR/09/035) (Unpublished). By Mark Woods.
    Available online at:
    Weymouth Relief Road: Temporary Excavations in Jurassic and Cretaceous Strata. Mark Woods, BGS.
    This report provides a stratigraphical overview of Corallian, Purbeck and Chalk Group temporary exposures, created in April and May 2009, in connection with the construction of the new Weymouth Relief Road. At the time of report compilation, the key exposures seen are in the upper part of the Corallian Group (Clavellata Formation), lower to middle Purbeck Group (Worbarrow Tout Member & basal Stair Hole Member) and White Chalk Subgroup (including Seaford Chalk Formation and Newhaven Chalk Formation).
    (see also Geology of the Ridgeway Railway Cutting and Weymouth Relief Road. Ian West 2009.)

    Woodward , H. B. 1879. On Branchipus , Eocene Gurnet Bay, Isle of Wight. Quarterly Journal of the Geological Society, London , 35, 342-350. [with description of Archaeoniscus brodiei].

    Woodward, H.B. 1890. The geology of Swanage. In Braye, J. (ed.) 1890. Swanage (Isle of Purbeck) : Its History, Resources as an Invigorating Health Resort, Botany and Geology. 2nd Edition, Willaim Henry Everett and Son, Fleet Street, London, 119 pp.

    Woodward, H.B. 1895. The Jurassic Rocks of Britain. Vol 5. The Middle and Upper Oolitic Rocks of England (Yorkshire excepted). Memoirs of the Geological Survey of the United Kingdom. 499pp.

    [The following example extract is from pp. 236-238 on the Organic Remains of the "Purbeck Beds" or Purbeck Group. It has been reproduced in Strahan (1898), pp. 86-90 and includes figures and footnotes which are not given here. Please note that this present reproduction is for historic interest and to show the type of content of the book; it is also to give something something of an old broad overview of Purbeck faunas. It should not, however, be used by students or beginners for serious purposes (details and fossil names may be wrong) - refer to modern literature for a much more complete listing of Purbeck faunas!]

    The Purbeck Beds have yielded an exceedingly varied series of fossils. Perhaps of the highest interest are the Mammals, which at present have been obtained only from the base of the Middle Purbeck Beds of Durlston Bay-in a thin earthy or "Dirt" layer - in the very bed in which Forbes suggested they might be found.
    We are indebted to W. R. Brodie, of Swanage, and Charles Willcox, for the discovery of Spalacotherium in 1854, and two years later S. H. Beckles obtained a number of additional forms, including Plagiaulax. These fossils are far from abundant, and long and patient search may be unrewarded. In 1880, after 10 days' search, Mr. E. W. Willett obtained one specimen of Triconodon mordax.
    At least 12 genera and 22 species of Mammals have been described. They are Marsupials, insectivorous and herbivorous in habits, and are of diminutive size. The principal genera, such as Spalacotherium, Triconodon, and Plagiaulax, have been described by Sir Richard Owen and Dr. H. Falconer. Until recently no such remains had been found in the Wealden formation, and it is therefore interesting to note that a spccimcn described by Mr. A. Smith Woodward as Plagiaulax Dawsoni, and another, described by Mr. Lydekker as Bolodon, have been obtained from the Wadhurst Clay, near Hastings.
    No traces of Birds have as yet been found. Remains of Frogs were recorded from the Purbeck Beds of Swindon, by Charles Moore, but their occurrence is considered exceedingly doubtful by Mr. E. T. Newton. Among the fossils from the Purbeck Beds the Saurian remains are important. The Dinosaurs include Iguanodon and Nuthetes; then we have the "Swanage Crocodile," Goniopholis crassidens, and the dwarf Crocodiles known as Nannosuchus and Theriosuchus. Owen estimates the average length of a mature Theriosuchas at eighteen inches. Turtles have been obtained mostly from the quarrymen, as they occur in the stone-beds: they include Tretosternum, Pleurosternum concinnum, P. Bullocki, and Chelone obovata, some fine specimens of which are preserved in the museum at Corfe Castle. The Fishes include Asteracanthus verrucosus, Caturus, Coccolepis, Hybodus, Lepidotus, Macrosemius, Ophiopsis, and Pleuropholis, and they are mostly found in the stone-beds worked at the quarries. Specimens occur at various horizons in the Purbeck Heds, and some of the best preserved examples have been obtained from the neighbourhood of Teffont Evias, in the Vale of Wardour.
    It was the intention of Edward Forbes to publish an account of the Invertebrata of the Purbeck Beds of Dorsetshire; and he had assigned names to a number of new species of Mollusca, which he was the first to discover. Some of these have been figured in Lowry's Chart of Characteristic British Fossils, and others in works published on the Continent. They all belong to living genera, and taken by themselves, possess a Tertiary or even recent aspect.
    Reference has already been made to the principal genera of Mollusca found in the Purbeck Beds, but it may be mentioned that Mr. Carruthers has described, under the name Teudopsis Brodiei, a cuttle-bone from these strata in Dorset.
    Insects are represented very fully by remains of Coleoptera, Orthoptera, Diptera, Neuroptera, and Hemiptera. To the various remains very numerous names were applied by Prof. Westwood, and for our knowledge of these Insects we are chiefly indebted to the Rev. P. B. Brodie. There were Butterflies, Beetles, Dragon-flies, Locusts, Grasshoppers, Ants, and the earliest known Aphides; forms that are considered to indicate temperate conditions.
    At Durlston the Insect-remains occur most abundant in the Lower Purbeck Beds, elsewhere they are found in Middle Purbeck strata.
    Among Crustacea, the Isopod Archaeoniscus occurs in profusion in the Middle Purbeck Beds in the Vale of Wardour. It has been found, however, in the Lower Purbeck Beds of Wiltshire and Dorset.
    In 1850 Edward Forbes named eight species of Ostracoda ( "Cyprides") from the Purbeck Beds of Dorsetshire, but unfortunately he never described them. Figures of these species, reduced from diagrams used by Forbes in his lectures at the Royal School of Mines, were afterwards published by Lyell. It has not, in every case, been possible to identify the specimens upon which the names of these species were based, while some doubts have arisen concerning the particular horizons from which they were obtained. These difficulties have been pointed out by Prof. T. Rupert Jones, and more recently he has given a full account of the subject, with a revision of the names and descriptions of new species. These are for the most part freshwater forms, but the genus Cythere is marine, and Candona is said to be estuarine. Among the Ostracods it is found that Cypris purbeckensis, Candona ansata, and C. bononiensis are most abundant and characteristic in the Lower Purbeck Beds; Cypridea granulosa in the Middle Purbeck; and C. punctata in the Upper Purbeck. Their particular range was not, however, restricted, and it is interesting to note that Prof. Jones has recorded Cypris purbeckensis, and a variety of Cypridea tuberculata, from the Upper Cretaceous strata of Wyoming, in North America.
    Here and there at various horizons in the Middle and Lower Purbeck Beds a number of "Dirt Beds" occur. The name has been applied to layers of carbonaceous clay or shale, but it originated in Portland Island, where the Great Dirt Bed which occurs near the base of the Lower Purbeck Beds is especially noted for the silicified remains of Cycads and Coniferous trees which it has yielded. There great" Burrs" of siliceous and calcareous (tufaceous) material have been accumulated around the old tree stumps, an example of which seen in the cliffs east of Lulworth Cove is shown Fig. 128, and another at Portisham is shown in Fig. 130.
    A bed yielding similar more or less silicified plant-remains has been observed near Lulworth and eastwards to Gad Cliff; and there are traces of Burrs to the east of Dancing Ledge as observed by Mr. Strahan and myself in 1893.
    Chara was found in the cherty freshwater band of the Middle Purbeck Beds by Edward Forbes.
    The following may be included as among the more common and characteristic fossils of the Purbeck Strata [Fig numbers are in the original but not given here. Of course this is a very old list and is here for historic reasons only and not intended for serious use at the present day. These names are frequently out-of-date but I have translated a few]:

    [Gastropods - see also Arkell - Gastropods of the Purbeck Beds, and later work.]
    Melanopsis harpaeformis. [Pychostylus harpaeformis]
    Paludina carinifera. [Viviparus cariniferus]
    Paludina elongata . [Viviparus elongata]
    Physa Bristovii. [Physa bristovii]

    Corbula alata.
    Cyrena (Cyclas) media. [Neomiodon?]
    Cyrena (Cyclas) parva. [Neomiodon?]
    Ostrea distorta.
    [the well-known oyster of the Cinder Bed - Praeexogyra distorta]
    Unio compressus.
    Unio valdensis.

    Archaeoniscus Brodiei. [Archaeoniscus brodiei]

    [Ostracods - refer to Anderson and later papers.]
    Candona ansata.
    Candona bononiensis.
    Cypridea granulosa.
    Cypridea punctata.
    Cypris purbeckensis.

    [Echinoid - of the Cinder Bed]
    Hemicidaris purbeckensis.

    [Cycadophytes - of the Purbeck palaeosols - Dirt Beds]
    Mantellia microphylla.
    Mantellia nidiformis.

    [also Conifer
    Protocupressinoxylon purbeckensis

    and many other fossils not listed here]

    Worssam , B.C. and Ivimey-Cook, H.C. 1971. The stratigraphy of the Geological Survey borehole at Warlingham, Surrey. Bulletin of the Geological Survey of Great Britain, 36, 1-146. [Purbeck with evaporites is in the sequence.]
    Wright , J.L. 1999. Ichnological evidence for the use of the forelimb in iguanodontid locomotion. Cretacesous Fossil Vertebrates: Special Papers in Palaeontology Series, 60, 209-219. Abstract: Most modern reconstructions of iguanodontids in a quadrupedal walking posture show the forelimbs placed slightly closer to the midline than the hindlimbs, with the dorsal surface of the manus facing forwards. This posture is problematical because it would have required rotation of the radius around the ulna leading to distortion and dislocation of the joints at the wrist or elbow. Some unusual trackways from the Purbeck Limestone Group (Upper Jurassic-Lower Cretaceous, UK) which show manus impressions are attributed herein to iguanodontids, challenging previous ideas regarding placement of the manus during the locomotion of these dinosaurs. The manus impressions are oriented with the palmar surfaces facing inwards towards the trackway midline, thus digit I would have faced anteriorly rather than medially. This obviates the need for unnatural twisting of the bones of the lower forelimbs. In addition, these trackways show foot emplacement patterns characteristic of a facultative quadruped. The manus impressions lie in two lines on either side of the single line formed by the pes impressions, indicating that, when walking quadrupedally, the forefeet were placed in a wider trackway than the hindfeet.

    Wright, J.L., Unwin, D.M., Lockley, M.R. & Rainforth, E. 1997. Pterosaur tracks from the Purbeck Limestone Group of Dorset, England. Proceedings of the Geologist's Association, 108, 39-48. Abstract: Purbeckopus pentadactylus, an unusual vertebrate track, is found in the Intermarine Member of the Purbeck Limestone Formation (Lower Cretaceous) of southern England. Only three slabs of biosparrudite containing the trace fossil have been found. These rocks were deposited on intertidal to supratidal flats. Purbeckopus is a quadrupedal vertebrate trace comprising a tetradactyl elongate subtriangular plantigrade pes and an elongate tridactyl manus. It is very similar td the ichnogenus Pteraichnus (Stokes) and it seems likely that both tracks were made by the same type of animal. Re-examination of Purbeckopus led us to the conclusion that it is probably pterosaurian in origin. This conclusion is based on two main features of the tracks. Firstly, the pes tracks show indications of elongate penultimate phalanges, a pterosaur characteristic. Secondly, the trackway has an unusual configuration wherein the impression of the manus lies well outside that of the pes. Only an animal with forelimbs longer than hind limbs would be likely to make such a track. The pterosaur that produced Purbeckopus is calculated to have had a wingspan of approximately 6 m. The identification of Purbeckopus as a pterosaur track indicates that large pterosaurs must have existed somewhat earlier than previously thought.
    Wright, V.P. and Platt, N.H. 1995. Seasonal wetland carbonate sequences and dynamic catenas: a reappraisal of palustrine limestones. Sedimentary Geology, 99 (1995), pp. 65-71.

    Wright, V.P., Platt, N.H., Marriott, S.B. and Beck, V. A classification of rhizogenic (root-formed) calcretes with examples from the Upper Jurassic-Lower Cretaceous of Spain and Upper Cretaceous of southern France. Sedimentary Geology, 100 (1995), pp. 143-158.

    Wright, V.P. and Azeredo, A.C. 2006. How relevant is the role of macrophytic vegetation in controlling peritidal carbonate facies?: Clues from the Upper Jurassic of Portugal. Sedimentary Geology, 186, Issues 3-4, 1 May 2006, Pp. 147-156. By V. Paul Wright (Cardiff University) and Ana C. Azeredo (Universidade de Lisboa, Portugal). The complete paper is available online from Science Direct (Elsevier).
    Abstract: Stratigraphic variability in peritidal carbonates is generally interpreted in terms of sea-level changes, but little consideration is given to the effects of vegetation and of how long-term changes in macrophyte evolution have affected carbonate sedimentation in such settings. Many present day low energy tropical carbonate shorelines are dominated by macrophyte vegetation. Although several pre-Jurassic macrophytes have been interpreted to have lived in brackish-water zones, records of macrophyte-dominated carbonate shorelines in the stratigraphic record are apparently rare or even absent, which thus is an enigma. We use Upper Jurassic platform interior carbonates from central Portugal to emphasize these issues; these successions contain both classical tidal flat-bearing cyclothems and ones capped by marsh facies with evidence of macrophytes, the former having developed in more restricted settings. Although these late Jurassic shorelines were not affected by true mangroves, we propose that tidal flat deposits were not developed because the shorelines, at least locally, were dominated by macrophytes. We speculate that the paucity of classical tidal flat-bearing peritidal cyclothems in the Cainozoic may have been due, at least partially, to the spread of major macrophyte-dominated mangrove communities during the Paleogene.
    [This is not on the Purbeck Group or strata of exactly the same age. It is relevant because it does discuss Upper Jurassic strata with some facies similarities to the Purbeck strata of Dorset, including the presence of "Black Pebbles".]


    Young, H.R. 1977. Evidence of former evaporites in the Cambro-Ordovician Durness Group, northwest Scotland. Sedimentary Geology, vol. 22, issues 3-4, March, 1979, pp. 287-303. Accepted 8 June 1978. Available online 8 April 2003.
    Quartz nodules, exhibiting the morphology of nodular anhydrite, occur in two zones near the top of the Sangomore Formation (Cambro-Ordovician Durness Group) in a section on Balnakiel Bay, northwest Scotland. The nodules, up to 4 cm in diameter, occur in thinly laminated dolomite and are composed of megaquartz and length-slow chalcedony (lutecite and quartzine). Lath-like textural relicts, outlined by opaque inclusions, and minute crystals of anhydrite occur in the megaquartz and lutecite. The quartz nodules are interpreted as silica pseudomorphs after early diagenetic anhydrite nodules which developed in a peritidal setting. Quartz nodules in stratigraphically higher parts of the Durness Group may record the existence of other peritidal sediments in the same geographic area.
    Young, J.T. 1878. On the occurrence of a freshwater sponge in the Purbeck Limestone.Geological Magazine for 1878, vol. 15, pp. 220-221. [The discovery of Spongilla purbeckensis. This is the only known British Jurassic Monactinellid sponge, according to Arkell (1953). However, Clements in 1967 considered that the supposed monactinellid sponge spicules are not fossil at all but are actually the common silica pseudomorphs after lenticular crystals of gypsum, that were described in West (1964). See also Hinde (1893).]

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    Zanella, A., Cobbold, P.R. and Rosjas, L. 2013. Beef veins and thrust detachments in Early Cretaceous source rocks, foothills of Magallanes-Austral Basin, southern Chile and Argentina: structural evidence for fluid overpressure during hydrocarbon maturation. Marine and Petroleum Geology, [in press, accepted manuscript, available online, 26th October, 2013.] By Alain Zanella, Peter R. Cobbold and Lisandro Rojas, Zanella and Cobbold adress: CNRS and Universite de Rennes 1, 35042 Rennes, France. Rojas address: ENAP-SIPETROL, Avenida Vitacura 2736, Santiago, Chile.
    Zanella et al. 2013. Beef Veins - Chile. Part available online.
    [Highlights: In Tierra del Fuego, subsurface and surface data have revealed thrust detachments. Thrust detachments and bedding-parallel veins (beef) are within the source rock. Calcite beef contains hydrocarbons and occurs in mature source rock (oil window). Quartz beef occurs where the source rock is very mature or overmature. The maturation leads to overpressure, hydraulic fracturing and thrust detachments.]
    We describe (1) bedding-parallel veins of fibrous calcite (beef) and (2) thrust detachments, which we believe provide good evidence for fluid overpressure in source rocks for petroleum. Our examples are from the surface or subsurface of the Magallanes-Austral Basin, which lies at the southern tip of South America. There, the best source rocks for petroleum are of Early Cretaceous age. In the central parts of the basin these source rocks have become overmature, but at the eastern edge, onshore and offshore, they are today either immature or in the oil window.
    In Tierra del Fuego, the foothills of the Andes consist mainly of sedimentary rocks, which have undergone thin-skinned thrusting. In the Vicuna area (Chile), Early Cretaceous source rocks have reached the surface above thrust detachments, which are visible on seismic data and well data. At the surface, we have found calcite beef, containing hydrocarbons (solid and/or fluid), in the Rio Jackson and Vicuna formations, which have reached the wet gas window. In the Rio Gallegos area (Argentina), the source rocks have not reached the surface, but seismic and well data provide good evidence for thin-skinned thrusting above flat-lying detachments in Early Cretaceous source rock, where it is in the early oil window. In contrast, there is little or no deformation where the source rock is still immature. Thus the deformation front coincides with the maturity front. Next to the central parts of the basin, where the source rocks have reached the surface within the Andes proper, they have undergone low-grade metamorphism. Within these source rocks, we have found beef veins, but of quartz, not calcite. To the east, within the foreland basin, seismic and well data provide evidence for a few compressional structures, including thin-skinned detachments in the deeply buried source rock. Finally, in the northern part of the basin (Santa Cruz province, Argentina), where it is shallower, the source rocks have reached the surface in the foothills, above a series of back-thrusts. At Lago San Martin, the source rocks have reached the oil window and they again contain calcite beef.
    In conclusion, where we have examined Early Cretaceous source rocks at the surface, they contain either calcite beef (if they have reached the late oil window or wet gas window) or quartz beef (if they are overmature). Independent evidence for overpressure, in the form of source-rock detachments, comes from subsurface data, especially at the southern end of the basin, where the source rocks are not overmature and deformation is relatively intense. Thus we argue that hydrocarbon generation has led to overpressure, as a result of chemical compaction and load transfer, or volume changes, or both.

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    Zakharov , V.A. and Rogov, M.A. 2008. Let the Volgian stage stay in the Jurassic. Russian Geology and Geophysics, 49, (2008), 408-412.
    In 1996 the Volgian Stage was divided into the Jurassic and Cretaceous units, removed from the Geological Time Scale, and substituted by the Tithonian Stage according to the guidelines of the Interdepartmental Stratigraphic Committee of the Russian Federation (ISC RF). Consequently, the Upper Volgian Substage including three zones (five subzones) was placed into the Berriasian Stage (the Cretaceous) proceeding from ammonite fauna, and the Cretaceous lower boundary was defined by the base of the Kachpurites fulgens Zone. Some stratigraphers, however, contested that decision and suggested to restore the former status of the Volgian Stage. Their idea has been validated by magnetostratigraphic studies carried out in 2003 in Jurassic-Cretaceous boundary strata in the Nordvik Peninsula (the Laptev Sea), which bear the most complete record of Boreal deposition and biostratigraphy. The new data prove that the Volgian Stage, in its nearly full stratigraphic volume, rather belongs to the Jurassic period.

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    BIBLIOGRAPHY CONTINUES AS: Purbeck Bibliography - by Topics |

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    I am much obliged to Francis Charig for further information on the Purbeck dinosaur footprints shown in relation to the reference to Dr Alan Charig. I am very grateful for various reprints and information on papers.
    The support of my wife Cathy has made possible the work on these webpages, and of course this is very much appreciated.

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    Dr Ian West, author of these webpages

    Webpage - written and produced by:

    Ian West, M.Sc. Ph.D. F.G.S.


    at his private address, Romsey, Hampshire, kindly supported by Southampton University,and web-hosted by courtesy of iSolutions of Southampton University. The website does not necessarily represent the views of Southampton University. The website is written privately from home in Romsey, unfunded and with no staff other than the author, but generously and freely published by Southampton University. Field trips shown in photographs do not necessarily have any connection with Southampton University and may have been private or have been run by various organisations.