West, Ian, M. 2O18. Barton and Highcliffe, Eocene Strata: Geology of the Wessex Coast of southern England. Internet site: www.southampton.ac.uk/~imw/barton.htm. By Ian West, Romsey and Southampton University. Version: Revised, 27th November 2O18, update in progress. Version Sun 25 [Section 6 updated]

Barton-Heading-Eocene-Pleistocene

Ian West,
Romsey, Hampshire

and Visiting Scientist at:
Faculty of Natural and Environmental Sciences,
Southampton University,

Webpage hosted by courtesy of iSolutions, Southampton University
With some aerial photographs by courtesy of The Channel Coastal Observatory , National Oceanography Centre, Southampton.

See also the related webpage on coastal erosion and sea defences at Barton-on-Sea:

Barton and Highcliffe - Geology - Coast Erosion

MORE BARTON AND HIGHCLIFFE WEBPAGES
Barton-on-Sea and Highcliffe - Geological Field Guide - this webpage
Coast Erosion and Sea Defences at Barton-on-Sea and Highcliffe
Barton and Highcliffe - Erosion History
Highcliffe, Barton and Hordle - Bibliography
Hengistbury Head (Lower Barton Clay) and Mudeford Spit

|Home and List of Webpages
|Field Guides Introduction. |Barton and Highcliffe - Coast Erosion - General |Barton and Highcliffe - History of Coast Erosion at Barton |Hordle Cliff and Milford-on-Sea |Hurst Spit |Highcliffe, Barton and Hordle - Bibliography |New Forest Geology | Hengistbury Head |Solent Estuaries |Brownsea Island, in Poole Harbour |Bournemouth Cliffs

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CONTENTS OF THIS BARTON WEBPAGE:

CONTENTS - SECTION 1 - INTRODUCTION - GENERAL
1.1. INTRODUCTION - General - [working correctly]
1.2. INTRODUCTION - Safety at Barton-on-Sea, Highcliffe and adjacent coast - [working correctly]
1.3. INTRODUCTION - Barton-on-Sea Geology, First Impressions [working correctly]
1.4. INTRODUCTION - General - Area and Strata Discussed [working correctly]
1.5. INTRODUCTION - Age of the Barton Clay [working correctly]
1.6. INTRODUCTION - Middle Eocene Climatic Optimum (MECO) [working correctly]

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CONTENTS - SECTION 2 - INTRODUCTION - MAPS
2.1. INTRODUCTION - Topographic Maps [working correctly]
2.2. INTRODUCTION - Geological Maps [working correctly]
[For Palaeogeographic Maps and Palaeogeography - not here - see Palaeogeography Section 9]

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CONTENTS - SECTION 3 - EOCENE STRATIGRAPHY - INTRODUCTORY
3.1 STRATIGRAPHY - Introduction Eocene - General
3.2 STRATIGRAPHY - Barton Clay Formations - General
3.3 STRATIGRAPHY - Barton Sand Formations - General
3.4 STRATIGRAPHY - Bartonian Strata of Paris -

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CONTENTS - SECTION 4 - LOWER BARTON CLAY - STRATIGRAPHY AND SEDIMENTOLOGY - DETAILS
4.1 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - General
4.2 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Basal Pebble Bed
4.3 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Prestwichianus Bed
4.4 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Hengistbury Head Succession
4.5 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Seismites
4.6 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Clay Mineralogy
4.7 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Geochemistry
4.8 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Miscellaneous
4.9 STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Extra

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CONTENTS - SECTION 5 - MIDDLE BARTON CLAY - STRATIGRAPHY AND SEDIMENTOLOGY - DETAILS
5.1 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - General
5.2 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay -
5.3 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Clay Mineralogy
5.4 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Geochemistry
5.5 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Sedimentology Structures - Septarian Nodules
5.6 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Clay Mineralogy
5.7 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Geochemistry
5.8 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Miscellaneous
5.9 STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - Septarian Nodules

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CONTENTS - SECTION 6 - BARTON SAND GROUP = CHAMA SAND FM. AND BECTON SAND FM.
STRATIGRAPHY AND SEDIMENTOLOGY - DETAILS [corrected and links working]

6.1 STRATIGRAPHY AND SEDIMENTOLOGY - Becton Sand Group - General [link working]
6.2 STRATIGRAPHY AND SEDIMENTOLOGY - Becton Sand Group - [link working]

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CONTENTS - SECTION 7 - PALAEONTOLOGY - BARTON FOSSILS

7.1 FOSSILS - Introduction
7.2 FOSSILS - Marine Shells
7.3 FOSSILS - Plant Fossils
7.4 FOSSILS - Plant Fossils - Palaeoclimatic Implications
7.5 FOSSILS - Fossil Whales (expanded section)

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CONTENTS - SECTION 8 - PALAEOGEOGRAPHY AND PALAEOCLIMATOLOGY
8.1 PALAEOGEOGRAPHY - General
8.2 PALAEOGEOGRAPHY -

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CONTENTS - SECTION 9 - QUATERNARY - PLEISTOCENE - HOLOCENE
9.1 PLEISTOCENE STRATA - Flint Gravels
9.2 PLEISTOCENE STRATA - Brickearth
9.3 CLIFF VEGETATION (AT PRESENT)

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CONTENTS - SECTION 10 - BEACH AND BEACH PROCESSES
10.1 BEACHES INTRODUCTION

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CONTENTS - SECTION 11 - SPECIFIC LOCATIONS [revised]
11.1 LOCATION - Mudeford to Highcliffe - Friars Cliff
11.2 LOCATION - Highcliffe, West of Chewton Bunny
11.3 LOCATION - Highcliffe, The Highcliffe Borehole
11.4 LOCATION - Highcliffe, East of Chewton Bunny
11.5 LOCATION - Barton-on-Sea - West of Barton Court
11.6 LOCATION - Barton-on-Sea - Cliff House - Hoskins Gap Area
11.7 LOCATION - Barton-on-Sea - Barton Court area
11.8 LOCATION - Barton-on-Sea - Barton Court East to Becton Bunny
11.9 LOCATION - Becton Bunny

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CONTENTS - SECTION 12. LANDSLIDES AND CLIFF FALLS
12.1 LANDSLIDES - Go to related webpage. Click -- Barton - Coastal Erosion and Landslides.

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CONTENTS - FINAL PART
13.1 ACKNOWLEDGEMENTS
13.2 BIBLIOGRAPHY AND REFERENCES

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1.1. INTRODUCTION TO BARTON-ON-SEA GEOLOGY - GENERAL
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[Historic note. I first visited Barton-on-Sea in 1942, staying as a child with my sister and mother at one of the newer coastguard cottages (built inland after the cliff edge coastguard cottages). We were not allowed down to the beach because of military defences, so my sister and I played on Barton Common, back from the barbed wire and mines of the cliffs. I became a Bournemouth resident (Gerald Road) during the Second World War and was at Bournemouth School and a member of Bournemouth Natural Science Society. After the war ended, the Barton Cliffs were accessible and within easy cycling distance and I was frequently out on the collapsing clay. The present sea defences had not been built. Fred Stinton of Bournemouth was also often collecting on the cliffs. 76 years later and as a sedimentologist, not a fossil collector, I am still regularly out on the Barton Cliffs. Ian West.]

A general view of the cliffs from Barton-on-Sea, Hampshire, in a westward direction, with gulls rising on the cliff thermals

General view of the central part of the sea front at Barton-on-Sea, an easily recognised location.

An introductory view of the shops at Barton-on-Sea, near Barton Court, and near the main car park and Hoskin's Gap, as seen in September 2018

Re: location. here is the small row of shops, next to Barton Court, which you should encounter when you drive to the coast at Barton-on-Sea. Go to the main car park, which is nearby, just a short distance to the west of these shops. At the car park, you can directly see some sea defences and some coastal erosion processes. There are some steps down at Hoskin's Gap which give easy access to the undercliff. You are then on the cliffs just seaward of the buildings shown.

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The greensward and cliff edge immediately to the west of Barton Court, looking southward in stormy weather, undated, perhaps about 2008

Descending to the Barton Cliffs at Barton-on-Sea

Locations at Barton-on-Sea, Hampshire - Hoskin's Gap, 2007

Above is shown, in an old photograph (2007), the Hoskin's Gap route down to the mid-cliff at Barton-on-Sea.

The sloping footpath down to the mid-cliff, just east of Barton Court, view late in the afternoon, 3rd September 2018, Ian West

Further down the sloping footpath down to the mid-cliff, just east of Barton Court, view late in the afternoon, 3rd September 2018, Ian West

You can go down to the Barton mid-cliff area by two routes. One is at Hoskin's Gap, adjacent to the main car park at Barton. You may use that as the quickest way from a car in the car park. Alternatively, especially if you are parked on the road, you may wish to descend immediately to the east of the Barton Court buildings. Photographs of this route are shown above.

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Descending to the Barton Clay Cliffs at Highcliffe

[from Highcliffe Beach Car Park]

There is easier access to the Barton Clay cliffs at Highcliffe, shown below. You can walk down directly to the clay cliffs. From the little bridge over the Chewton Bunny stream you can walk eastward towards Barton. Note that according to tide and cliff conditions you may or may not be able to get as far as Barton-on-Sea. It is easier and simpler to return to the Highcliffe car park.

Note that, in spite of landslipping cliffs, many years ago it was possible to walk easily between Highcliffe and Barton. This may be possible in dry weather conditions, or you may be obstructed by an impassable mudslide or even (less likely) by the tide up to the cliffs. Conditions and feasibility of access will vary. No route is guaranteed here, and note that trying to cross the muddy, treacherous cliffs is difficult and may be dangerous, especially to an inexperienced person. It is best to stay on the beach, provided tide conditions are suitable.

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Leaving the car park and cafe and beginning to walk down to the cliff section of Barton Clay at Highcliffe, 24th February 2017

Walking down from the car park at Highcliffe to the main cliff section of the Barton Clay, with Barton-on-Sea in the distance, 24th Februay 2017

The fossiliferous Barton Clay in the cliffs between Highcliffe and  Barton-on-Sea, Hampshire, with Imogen Loades, fossil collecting, 24th February 2017

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The Barton Clay of the cliffs of Christchurch Bay on the southern England coast is famous for its rich fossil content. The strata were better exposed in the past, when there were no sea defences and when there was less tendency for vegetation to grow on cliffs. Some superb fossil collections have been made and they are now preserved in various museums (such as at Bournemouth Natural Science Society for example). The stretch between Highcliffe and the first sea defences east of this at Barton-on-Sea is still good for fossil collecting. It is easy to access from Highcliffe but less so from Barton now because of sea-defences, cliff collapse and mudslides.

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1.2. INTRODUCTION - SAFETY AT BARTON-ON-SEA AND ADJACENT CLIFFS

- Particularly - mud - "quicksand" risk

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Soft mud, particularly in mudslides, is a serious risk in the cliffs between Highcliffe and Barton-on-Sea, Hampshire

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The sea attacks the soft muddy base of the Old Sea Road Mudslide at Barton-on-Sea, Hampshire, with remains of the drainage system in the sea, 28th January 2016

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This website is descriptive of the geology, and, of course, it advises safe procedures. However, it is not an itinery and it reommending any specific detailed action or procedure on the cliffs or coast. Visitors, field workers and field leaders should make their own assessment of safety matters. Some points are mentioned though. The main hazard at Barton-on-Sea, Highcliffe, and of Hordle Cliff is that of sinking into soft mud and becoming stuck. This is particularly a risk on landslides or mudslides or on the clay terraces above the beach level. It can be a worse problem in winter and spring (the cliffs may not dry out much until late April). The soft-mud risk to a person scrambling on the cliffs can be quite major in places. Once someone is stuck in mud by even one leg above the knee, it is extremely difficult to get out. The moving mud of mudslides has large hard lumps or blocks within it and cannot be simply dug out. Professional help might well be needed. I have seen a person stuck in mud there for several hours. In wet and muddy conditions it is wise to stay on the beach and collect from the lowest part of the cliffs.

On the Highcliffe and Barton coast sections with steep cliffs, as at Becton Bunny, there is a real risk of being struck by a falling rock, pebble or lump of mud. Where such risk are present avoid the area or at least keep well away from the cliff.

Landslides usually move slowly on the Barton Cliffs, but rapid movements are possible on rare occasions. Debris falls are common in certain areas and they can be dangerous. Debris is currently (2018) falling regularly in the retreating Becton Bunny area. Falls can also occur elsewhere. At the tops of the cliffs the Pleistocene gravel usually forms a vertical part of the cliff, often with overhangs. There can be falls of gravel from these uppermost cliffs. Falls of clay and possibly of carbonate nodules can occur at the lower sea cliffs.

A minor hazard is that adders (snakes) live on these cliffs but bites are very rare.

There is of course, some risk of falling from a cliff edge. It is, of course, hazardous to stand on the cliff-top of gravel close to the edge. At some places there is an overhang which might collapse. Injury from falling debris from the cliffs is possible to the east of Barton, particularly in the Becton Bunny area of rapid erosion. It is not a frequent hazard in other places, but it may be possible.

It is rare that rising tides cut off people at Barton-on-Sea and Highcliffe, although it could happen in unusual circumstances. Slipping or falling on hard rock armour can lead to injury and it is better not to scramble on it. It is obvious that one should not hammer flint pebbles, which give off dangerous splinters, but there is little reason to do so. There is a very small risk of being cut off in places by rising tide, but a sensible person is unlikely to be trapped in this way on the Barton coast.

Do not, of course, hammer flint pebbles because of the production of dangerous, fast splinters. Be well-aware of the hazards of climbing on angular rock armour blocks. If you fall then injury is quite probable. In severe storm conditions, keep well away from braking waves.

Individual geological visitors and field leaders should make their own risk assessment and no recommendation to take any risk is made in this or associated webpages and no liability is accepted.

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1.3. INTRODUCTION TO BARTON-ON-SEA GEOLOGY -

INTRODUCTION continued - Barton and the Barton Clay Formation

Basic Information

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Sea erosion of the foot of cliff of Barton Clay at Naish Farm, Highcliffe, Hampshire, 30 September 2006

The Barton Clay, the Barton Sand and the overlying Headon Hill Formation (of the Solent Group) form part of the well-known Hampshire Basin, and are exposed at Barton and Highcliffe in Christchurch Bay, and also at Alum Bay and Whitecliff Bay, in the Isle of Wight. The strata are of the Bartonian and Priabonian Stages of the Upper Eocene Series. In terms of age in years these strata were deposited between about 42.1 amd 35.4 million years (Harland et al., 1982). They correspond roughly in age with the famous Eocene gypsum deposits of Paris (from whence comes the name - Plaster of Paris).

The type-section of the Barton Clay and Barton Sand at Barton Cliffs on the mainland consists of sandy clays in the lower part , dark sandy clays and stiff drab clays in the middle part, and clayey sands and light-coloured sands in the upper part (29.26m). The total was given as 61.56m by Burton (1929) but Barton (1973) has more recently considered the Barton Clay to be thicker (46.4m) and given a total figure for the Barton Beds of 75.4m (note that Bristow, Freshney and Penn (1991) gave the range of the Barton Clay thickness in the Bournemouth area as 20 - 60m, less than this figure but probably based on Burton).

Most of the strata are very fossiliferous. The Barton Clay has yielded more than 500 species of fossil mollusc shells. These are quite robust and can easily be cleaned by simply washing them with a soft brush. They look much like modern subtropical shells but have lost their colour. The shell, though, is still of the original aragonite and only the organic matter has been lost. They range from minute corals (Turbinolia) and the little, prickly gastropod Typhis pungens to the robust and fairly common gastropod - Clavilithes macrospira to the rare fan-shell Hippochrenes amplus . The turreted gastropods Turritella imbricateria and Turritella sulcifera are very common, and sharks teeth and ray-fish teeth (see above) can be found from time to time. Both the sea-defences and the retreat of the coast away from the most fossiliferous strata has much reduced the fossil-collecting potential. Nevertheless good specimens can still be found in the Naish Farm area between Barton and Highcliffe, and the cliffs at the back of the beach here are well-worth a visit.

Not much of the Barton Clay can be seen from Barton eastward to the end of the Marine Drive East. The cliffs have large blocks of limestone at the base, some timber piles, much gravel spread above and some iron sheet-piling here and there. The engineering works also require roads or tracks for vehicles and machines. This central section is instructive with regard to the development of landslides, the use of and failure of sea-defences. It is also a good area to see the Pleistocene gravel at the top of the cliff and the yellow, oxidised Barton Sands or Becton Sand Formation. Apart from geologists it is of interest to geography students, environmental science students and civil engineering students. A visit is recommended.

East of Barton natural cliffs and good exposures start again near Becton Bunny. Longshore drift is from west to east because of the prevailing southwesterly winds. Much protective beach debris cannot get eastward past the Barton sea-defences, which are designed to hold it, so here there is terminal scour and enhanced coast erosion. This enables the Barton Sands or Becton Sand Formation to be seen in quite good exposures. There are some shells, of which the most robust is the white and conspicuous bivalve Chama squamosa of the Chama Bed. Above this horizon the bivalves and gastropods are thin-shelled, being of sheltered lagoonal or estuarine origin. The shells are not as strong or as abundant as in the Barton Clay.

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Some Introductory Historical Comments on the "Barton Beds" Nomenclature, after Bale (1984).

(The thesis on the Barton Clay by Professor Tunde Bale (1984) provides an historical introduction to the nomenclature of the Barton strata, referring, of course, to data before that date. An extract from p. 13 et seq. is reproduced here to show the discussion which has taken place. It is important to remember that this is old and that have been terminological changes since 1984.)

"The 'Barton Beds' first named by Gardner et al. (1888) are 'Upper Bagshot Beds' of the early nineteenth century workers, notable amongst whom was Prestwich (1846-1857). The deposit is mainly exposed in the cliffs of Highcliffe and Barton-on-Sea on mainland Hampshire and at Alum Bay and Whitecliff Bay on the Isle of Wight. The deposits have also been proved to exist below Southampton Water (Curry, Hodson and West, 1968) and below the Solent (Dyer, Hamilton and Pingree, 1969). Equivalents of the deposits have also been described from Afton and Gunville on the Isle of Wight (Curry, 1942) and the New Forest on mainland Hampshire. Gardner et al. provided a cyclothemic arrangement of the "Barton Beds" into "Lower, Middle and Upper divisions" with the "Lower and Middle Barton Beds" constituting the authors' [i.e. Tunde Bale's] "Barton Clay". Later, White (1921) defined the sands that dominate the Upper Barton, on the Isle of Wight, as the "Barton Sands". Burton (1929, 1933) further sub-divided the section on mainland Hampshire into fourteen units using letters for each; but with the lowermost three units being successively labelled A1, A2 and A3.

Stinton (1975) re-defined the "Barton Beds" as a formation - the "Barton Formation" - - including the overlying "Lower Headon Beds" (of Forbes, 1856, and Tawney and Keeping, 1883) as the uppermost unit of the formation. The "Lower, Middle and Upper Barton divisions" and the "Lower Headon Beds" successively became the "Highcliffe", "Naish", "Becton" and "Hordle" Members of the "Barton Formation". This definition was adopted by Curry et al. (1978) and Melville and Freshney (1982). Still, this does not strictly meet the ISSC guidelines and has particularly been opposed by Daley and Insole (1979). Objections arise from the fact the "Lower and Middle Barton Beds" are similarly clayey lithologically, whereas the "Upper Barton Beds" predominantly comprise sands. Furthermore, sediments of the "Lower Headon Beds" are mostly clayey and are actually lithologically indistinct from the succeeding "Middle Headon Beds" and the faunalistically similar "Upper Headon Beds". In fact, the "Headon Beds" constitute fresh-brackish water cyclothems of sands, clays, lignites and limestones (Forbes, 1856) that are distinct from the dominantly marine "Barton Beds". The distinction was realised and effected by West (1980), who grouped the "Headon Beds" together as the "Headon Formation". [end of historical introduction]

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Erosion of Christchurch Bay

The setting of Barton-on-Sea in Christchurch Bay is first shown in relation to Quaternary sea-flooding of palaeovalleys.

Palaeovalleys of Velegrakis et al. 1999 in Poole and Christchurch Bays

The cliffs of Barton-on-Sea are very new in geological terms. They are post-Neolithic, when there was a relatively low sea-level. The most recent rise in sea-level took place in only the last four thousand years, in effect a very short, almost trivial interval of time. This is so modern that it is almost archaeological rathe than geological. The former stream pattern under Poole and Christchurch Bays has been mapped by Velegrakis et al. (1999) and a map based on this is shown above. Christchurch Bay is so young that it has developed by rapid coast erosion after the formation of these, now-submerged stream valleys. It is not suprising because the cliffs of Eocene clays and sands are not at all resistant and can be and have been very rapidly eroded.

Examination of the map will show that even the sand and clay cliffs of Bournemouth have retreated more slowly than at Barton-on-Sea. A reason for this is that the Bournemouth cliffs have some partial protection from southwesterly storms by the projecting headlands of Durlston Head, Swanage and Handfast Point (Harry Rocks), also in the Swanage area. Southwesterly storm waves can reach the Barton Cliffs more easily.

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The Barton Clay Formation - Initial Introduction

The Barton Clay Formation, Middle Eocene, of Barton-on-Sea is remarkably fossiliferous. It originated in an embayment of a warm shallow sea, at about 40 degrees north. The date of formation approximately corresponded to the Middle Eocene Climatic Optimum, the MECO. There are fossil remains of numerous gastropods and bivalves, still preserved as aragonitic shells. Sharks teeth are common, and notable features are the bones of early cetaceans (whales) of sea serpent appearance. They are like the famous early whales of Wadi El-Hitan, Egypt, but slightly older. Excellent fossil collections have been made of the well-preserved and uncrushed fossils of the Barton Clay. Rapid erosion of the cliffs here has made this a particularly good place for collecting fossils.

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An general view of the Eocene, fossiliferous cliffs from Highcliffe to Barton-on-Sea, Hampshire, August, 2016

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Septarian nodules from the base of Bed C of the Barton Clay being eroded out at the foot of the cliffs at Naish Farm, near Highcliffe during a storm in October 2006

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Alum Bay, Isle of Wight, with Barton Clay in the cliff, seen with telephoto lens, in the distance from Barton-on-Sea, Hampshire, 3rd September 2018

A rain squall over the western part of the Isle of Wight seen from Barton-on-Sea, Hampshire, November 2009

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An old photograph of the cliffs at Barton-on-Sea, Hampshire, in the 1950s or early 1960s before sea defences were constructed

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Cliffs at Barton-on-Sea, Hampshire, looking westward, in the 1950s before there were any major sea defences

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Barton Clay, Highcliffe, 07.03.01, clay cliffs steaming as the sun heats them up, in 2001

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Rapid cliff erosion of the Barton Sand Formation, east of Barton-on-Sea, with the Chama Bed at beach level in 2002

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The Barton Clay Formation is Bartonian, a stage of the Upper Eocene. The Barton Beds are of Upper Eocene age. The area was covered with an inland sea, at a palaeolatitude of about 40 degrees N. The temperature was significantly higher than at the present day. The name, of course, comes from Barton-on-Sea in Hampshire, southern England. The stage name "Bartonian" was introduced by Karl Mayer-Eymar in 1857 and intended for the continental equivalents of the series.

The Barton Group consists of the Barton Sand Formation, Barton Clay Formation, Chama Sand Formation, and Becton Sand Formation (informally known as the "Barton Sands"). At Hengistbury Head the Barton Clay contains a sand member, the Warren Hill Sand, forming the upper part of the cliff, at the higher, western part of the hill. See Bristow, Freshney and Penn (1991) (see Chapter 6, Palaeogene - Barton Group)

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1.4. INTRODUCTION - General - Area and Strata Discussed

Barton-on-Sea, Hampshire

See Barton-on-Sea location on zoomable Bing aerial photographs and maps. See also Google Earth. Particularly see the Channel Coastal Observatory aerial photographs. .

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1.5. INTRODUCTION - Age of the Barton Clay

The Barton Clay of the Hampshire Coast and the New Forest is Upper Eocene. Referring to the Geologic Time Scale, 2012 version, the Bartonian Stage was given as corresponding to 41.2 to 37.8 million years ago.

[the following is from Wikipedia]

["The base of the Bartonian is at the first appearance of the calcareous nanoplankton species Reticulofenestra reticulata. In 2009, an official reference profile (GSSP) for the base of the Bartonian had not yet been established.
The top of the Bartonian stage (the base of the Priabonian) is at the first appearance of calcareous nanoplankton species Chiasmolithus oamaruensis (which forms the base of nanoplankton biozone NP18).
The Bartonian stage overlaps part of the upper Robiacian, European, Land Mammal Mega Zone (it spans the Mammal Paleogene zone 16), the upper Uintan and Duchesnean, North American Land Mammal Ages, part of the Divisaderan South American Land Mammal Age and is coeval with the Sharamururian Asian Land Mammal Age."] The Auversian regional stage of France is coeval with the Bartonian and is therefore no longer used

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1.6. INTRODUCTION - Middle Eocene Climatic Optimum (MECO)

The Barton Clay was largely deposited during the MECO, The Middle Eocene Climatic Optimum, although the exact relationship may not be very clear. In the Phanerozoic Geological Time Scale for 2012, the age of the Bartonian is given as between 41.2 and 37.8 million years. The middle Eocene climatic optimum (MECO) was a transient period of global warming that interrupted the secular Cenozoic cooling trend. It was from about 40.5 to 40.0 million years ago. Thus the middle part of the Barton Clay, with its abundant gastropod fauna, would seem to correspond quite well to this.

"Stable isotope data from Southern Ocean sites reveal anomalous temperature variability during the middle and late Eocene. The ca. 41.5 Ma middle Eocene climatic optimum event is interpreted to represent an important climatic reversal in the midst of long-term cooling in the middle to late Eocene, indicating that this trend was not entirely monotonic. If global in nature, the middle Eocene climatic optimum would represent one of the more rapid global warming events of the Cenozoic. Regardless of its full global extent, the middle Eocene climatic optimum is clearly an important event in the regional climatic history of the Indian-Atlantic region of the Southern Ocean. The rapidity and magnitude of warming (4 degrees C) imply that this climatic event dramatically affected both Southern Ocean biological communities and the coastal environments of Antarctica and Australia."

The above is from: Steven M. Bohaty and James C. Zachos, both from the Earth Sciences Department, University of California, Santa Cruz. In a 2003 article in Geology, entitled "Significant Southern Ocean warming event in the late middle Eocene".

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SECTION 2 - INTRODUCTION - MAPS

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2.1. INTRODUCTION - Topographic Maps

Maps and Locations

See also the Barton and Highcliffe Coast Erosion and Sea Defences webpage.

Location sketch map of the Barton and Highcliffe Coast, Hampshire

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Locations at Barton-on-Sea, Hampshire - Hoskin's Gap, 2007

Locations in the  Barton-on-Sea area, Hampshire, - the Chewton Bunny, Highcliffe Car Park

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2.2. INTRODUCTION - Geological Maps

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Old geological map of Hengistbury Head and Mudeford Spit, near Bournemouth, Dorset, revised to 1891

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Barton, Highcliffe and Hordle geological cliff section

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A selected part of the 1893 Geological Survey Map, Lymington Sheet, 330, Drift, original - one inch to one mile - it shows the coast from Barton-on-Sea to Hurst Spit

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The above map is a selected part after the 1893 edition of the Lymington Geological Survey Map. It shows central Barton and on towards Hurst Spit to the east. The western continuation of the coast with Barton Clay, is shown on the British Geological Survey Sheet, Bournemouth, Sheet 329. There is a very old edition of 1855 to 1856. The 1895 edition of the Bournemouth Sheet, one inch to one mile was reprinted in 1947. The Run extends almost to Highcliffe Castle on this old map. The current British Geological Survey Map for west of Barton is the 1991, England and Wales, Sheet 329, Bournemouth, Solid and Drift Geology, 1:50,000.

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SECTION 3 - EOCENE STRATIGRAPHY - INTRODUCTORY

3.1 STRATIGRAPHY - Introductory Eocene - General

A chart showing lithostratigraphic schemes for the Palaeogene strata of the Bournemouth and Poole area, including Brownsea Island and Barton-on-Sea

The sequence of Eocene strata at Hengistbury Head, Dorset, with comparison and correlation to the Boscombe Sands and Barton Clay section at Friars Cliff and Highcliffe

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3. STRATIGRAPHY continued

Succession of Strata

Eocene
 
 
 
Solent Group, Headon Hill Fm. (lower part only)
Becton and Chama Sand Fms. (Barton Sand)
Barton Clay Formation
Bracklesham Group, Boscombe Sands ("Mudeford Sands" or "Highcliffe Sands" at Friars Cliff)
 
29m.
46.4m.
>12m.

Thicknesses are from Barton (1973). The Plateau Gravel of Pleistocene age lies unconformably on the Barton Clay and Barton Sand (Chama Sand and Becton Sand). The Brickearth at the top of the gravel is a periglacial silt deposit, light brown in colour.

Barton-on-Sea, Hampshire

Above is the key diagram of the Eocene sequence here (click or double-click to enlarge!). To study the Highcliffe, Barton and Hordle Cliff sections successfully the field geologist should as far as possible commit this sequence to memory, keeping a paper copy at hand to remind him or her of the details. This is because parts of the section are obscured by sea defences and much is slumped in the cliffs or is overgrown with vegetation.

As is always the case when dealing with cliff sections look first for conspicuous markers and work from those. The basal pebble bed which lies above a sandstone cliff - Friars Cliff is obvious. The basal clay of the Barton Clay can be seen, with the approximate position of the Nummulites prestwichianus bed (although in poor condition now). A1 and A2 are not properly exposed now because of sea defences at Highcliffe. A3 might be seen at the western base of the Naish Farm section, depending on coast erosion and extent of slumping of the cliffs. Bed C, the Voluta suspensa is very obvious and occupies much of the lower cliff between Naish Farm and the first Barton sea defences. It cannot be missed because of the septarian nodules above and below, and also the pale, bored bed in the centre. D, E and F are now seen in limited slumped exposures in the cliff, often of difficult access (because of risk of sinking in). Exposures of G, the Stone Band (or Shell Bed) are not as common as in the past but might be seen here and there in the Barton landslides. The Chama Bed can often be seen at the foot of the cliff at the eastern end of the Barton Sea Defences, near Becton Bunny. Beyond the the Barton Sands or Becton Sand succession is quite clear and easily studied near Becton Bunny. The Lignite Beds, L, are two conspicuous black bands seen in Beacon Cliff. The Headon Hill Formation is fairly well exposed in Beacon Cliff and Hordle Cliff and for further information on this see the Hordle Cliff webpage.

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3.2 FORMATIONS - Eocene Strata
The (Palaeogene) Upper Eocene, Barton Group overlies the Middle Eocene Bracklesham Group, which is seen in the Bournemouth Cliffs. The British Geological Survey Memoir for Bournemouth (Bristow, Freshney and Penn, 1991) classified the Barton Group as consisting of the Boscombe Sand, the Barton Clay, the Chama Sand and the Becton Sand Formation. Perhaps the only controversial aspect of this, is whether the Boscombe Sand should be included in the Barton Group. However, it is simpler and best to use the British Geological Survey scheme, and the Bournemouth Memoir should be consulted (although this memoir only reaches the western part of the Barton Cliffs.

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3.3 FORMATIONS, MEMBERS AND BEDS

3.3 MIDDLE BARTON CLAY - BED C - CLAYS AND NODULES

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A general view of Bed C, the Voluta suspensa Bed, in dry summer weather near Highcliffe, Hampshire, with Barton-on-Sea to the east, August 2016

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The Voluta suspensa Bed or Bed C of the Middle Barton, in a cliff section in the Naish Farm area, east of Highcliffe

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Voluta suspensa Bed or Bed C, with the White Band in the middle and the septarian nodules near the top, just beneath the C-D slip-plane, Barton-on-Sea, Hampshire, 18th August 2016

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Horizontal landslide movement at the D shear surface, seen in the D scarp, between Naish Farm and Sea Road Access, Barton-on-Sea, Hampshire, 2006

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The bioturbated or burrowed band in the centre of Bed C of the Barton Clay, at the eastern end of the Naish Farm area, Hampshire

The Middle Barton Beds includes the part of the Barton Clay still visible in the cliffs in spite of sea-defences. It is seen from Chewton Bunny at Highcliffe eastward to Barton-on-Sea, with the best section at Naish Farm just east of Highcliffe. The Barton Clay of the Middle Barton Beds is more truely argillaceous than the Lower Barton. The large, spectacular fossil shells of the Barton Beds have mostly come from these clays, although it is less easy now to find such specimens than in the past. Sharks teeth are present here (as in the Lower Barton). This sequence has septarian nodules of argillaceous limestone, usually with some sand and some glauconite. The lowest two layers are of rounded nodules, but only the one at the top of Bed C, the Voluta suspensa Bed, is well exposed at present. Two upper bands of nodules were originally visible, but now the upper part of the cliff is either badly slumped or covered with sea-defences, so that only one is easily found. [NEW TEXT 16 ADDED AUG. 16]

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3.4 FORMATIONS - SUPPLEMENTARY NOTES - THE BARTONIAN GYPSUM OF PARIS, FRANCE

[section in preparation]

The Bartonian gypsum deposits of Paris, France, are famous. They are notable for vertebrate fossil remains. In sedimentological terms they are of particular interest in showing semi-arid conditions. Evaporites are not present in the Upper Eocene of southern England except for small amounts, replaced by silica, at Gurnard Bay on the Isle of Wight. Evaporite gypsum has not been found in the main Barton Clay section, although appreciate that secondary selenite from weathering of pyrite, not evaporitic, is common.

18O and 34S in the Upper Bartonium gypsum deposits of the Paris basin Fontes, J.C.; Letolle, R. (Universite Pierre et Marie Curie, Paris (France). Lab. de Geologie Dynamique) Citation Export Abstract [en] Isotopic analyses (18O and 34S) of the Eocene gypsum from the Paris basin show a range beyond the normal Tertiary marine values. The possibility of a reduction process during diagenesis is discussed. A hypothesis of continental origin by leaching of Permotriassic deposits is proposed for this formation on the basis of a comparison of the isotopic contents recorded from Germany and eastern France

[Relevant Paper - see:

Sequence Analysis of the Eocene-Oligocene Paris Basin, France J. P. Gely et C. Lorenz. 1991.

Abstract:
The Paris Basin (Map 1) is a classic example of a stable platform such as has been known throughout the World for a long time now. Aside from the Bartonian and Priabonian, all Eocene and Oligocene stages have been defined in the form of the following four international stratotypes : Sparnacian, Cuisian, Lutetian and Stampian. It should also be noted that the substages of the Bartonian (Auversian, marinesian) and the Ludian, the equivalent of the Priabonian, are also Parisian. Even though gaps have recently been redefined (C. Pomerol, 1989), though the correlations between the different formations in the basin and those of the surrounding areas (D. Curry, 1967; et al. 1969, 1978; C. Pomerol, 1977; C. Cavelier, 1979; C. Cavelier and C. Pomerol, 1986) have now been determined, and though the worldwide eustatic sea level curve was partly plotted with the help of stratotype sections (B. U. Haq et al. , 1988), the Eocene and Oligocene sequence analysis of the paris Basin has as yet only been roughly sketched out. The survey was not based on seismic profiles because the Parisian Tertiary series outcrop. Therefore, our analysis is based on field observations and the abundant bibliography dealing with the Paris Basin... continues:]

More to be added here.

Lacroix, A. 1897. Le gypse de Paris et les mineraux qui l'accompagnent. Classic work on the Paris gypsum.

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3.4 [empty, for future use]

[This section is not in use yet]

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SECTION 4 - LOWER BARTON CLAY - STRATIGRAPHY AND SEDIMENTOLOGY - SEDIMENTOLOGY DETAILS

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STRATA:

4.0 Lower Barton Clay - Description

See also the Barton and Highcliffe Coast Erosion and Sea Defences webpage.

A sign of coastal retreat - loss of beach material at Naish Farm, Highcliffe, Hampshire, revealing an erosional platform of Lower Barton, A2 grey-green clay, with fallen septarian nodules lying loose above

Lower Barton Clay exposed at low spring tide at Naish Farm, Highcliffe

Septaria washed out the Barton Clay at the scoured locality just east of Chewton Bunny, Barton-on-Sea, Hampshire

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Rather less than half of the Barton Clay belongs to the "Lower Barton Beds". Various authors, following Prestwich (1849), have taken the base of a pebble bed to be the base of the Barton Clay. It seems sensible to take what is probably a transgressive pebble bed as the base and that method is used here. Note, however, that Keeping (1887) and Curry et al. (1978) used the bottom of the Nummulites prestwichianus Bed, a little higher, as the base. This nummulite bed consists of green, glauconitic sandy clay. Most of the Lower Barton Beds which follow are rather sandy and they include the so-called Highcliff Sands of Gardner, Keeping and Monckton (1888) (not to be confused with the conspicuous sands of Bracklesham age at Friars Cliff). White (1917) summarised these beds. He stated that they take in a set of loamy sands with Voluta athleta (Sol.) and Cassis ambigua (Sol.) (now known as Volutocorbis ambigua (Solander)), and ends with rusty sand containing abundant Pholadomya margaritacea J. Sowerby. Unfortunately, with degradation of the cliff and with the construction of sea-defences little can be seen of these fossil beds now. The Lower Barton succession was said to be the richest in species of molluscs, with a large proportion resembling living forms from Australia and Japan, and seeming to indicate a considerable depth of water (White, 1917). Small corals (Turbinoliae), echinoderms (Ohphiura wetherelli Forbes, etc), claws of crabs, teeth of fish (Arius, Myliobatis, etc.), turtle bones, a few worn freshwater shells, and drift wood, are among other fossil remains present in these beds. For a full list see Burton (1933).

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4.1 - STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - General
The Lower Barton Clay is mainly exposed in the cliffs at Highcliffe, to the west of Chewton Bunny and also at Hengistbury Head. In the present state of weathering, it appears much less fossiliferous than the Middle Barton Clay. However, the cliffs to the west of Chewton Bunny are not appreciably eroded now. They are heavily protected by rock-armour, much of it Portland Stone, and if this is damaged or moved away by winter storms it is usually replaced and the cliff appears much the same.

Thus the Lower Barton Clay is of less interest to fossil collectors now. However, the teeth of sharks can sometimes be found because being of calcium phosphate, rather than calcium carbonate, they are less affected by acidic weathering.

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4.2 - STRATIGRAPHY AND SEDIMENTOLOGY - Basal Pebble Bed.
A distinctive pebble bed (or beds), with rounded, beach-battered flint pebbles, occur at the base of the Barton Clay at Hengistbury Head.

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4.3 - STRATIGRAPHY AND SEDIMENTOLOGY - Prestwichianus Bed
A nummulite bed with the small disk-like foraminifer Nummulites prestwichianus occurs near the base of the Barton Clay in the coastal section at Friars Cliff.

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4.4 - STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Hengistbury Head Succession

See the Hengistbury Head webpage for more information. After years of past dispute, the succession of strata at Hengistbury Head is now believed to correspond in large part to the Lower Barton Clay in the Friars Cliff to Highcliffe area. The sequence at Hengistbury Head is decalcified and thus fossils are difficult to find.

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4.5 - STRATIGRAPHY AND SEDIMENTOLOGY - Seismites

Beds showing contortions and liquifaction occur at Friars Cliff and less clearly at Hengistbury Head. These are almost certainly associated with the movement which was taking place on the Isle of Wight area. This was about the time of the first phase of major tectonic uplift. At Alum Bay and Whitecliff Bay the Middle Barton Clay Pebble Bed shows clear evidence of uplift and erosion of Cretaceous strata (down to the Upper Greensand) at this date. The earthquakes were probably associated with this.

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4.6 - STRATIGRAPHY AND SEDIMENTOLOGY - Barton Clay - Clay Mineralogy

Clay mineral data for the Lower Barton Clay has been given by Bale.

[some notes after Bale (1984), p. 26.]
"Gilkes (1966) [Professor Robert Gilkes] undertook [at Southampton University] the investigation of the clay mineralogy of the Palaeogene Beds of the Hampshire Basin, and found the clay mineralogy essentially comprised montmorillonite [now referred to as smectite], illite, kaolinite, traces of chlorite and some undifferentiated mixed-layer phases. In the Upper Eocene sediments, illite and montmorillonite dominated the clay mineralogy, with illite often constituting more than 40 percent of the clay fraction. Kaolinite, however, occurs in very high amounts in the Barton Sand and the 'Lower Headon Beds' at Heatherwood Point and Totland Bay on the Isle of Wight. The clay minerals are believed (Gilkes, 1966; Perrin, 1970) to have been derived from exposed Pre-Tertiar rocks located to the west and north of the basin. Recently, however, Gilkes (1978) re-explained the high illite contents of clay fraction in sediments of the "Lower Headon Beds" and the succeeding Oligocene sediments of the Isle of Wight as re-worked neoformed illites from very nearby sites. The author argued that illite neoformation could have occurred during dry periods within confined water-bodies, such as has been proposed in the Palaeogene sediments of the Paris Basin (Millot, 1970). The other minerals observed by Gilkes (1966) in the clay fraction were quartz, feldspars, anatase, calcite, siderite, goethite , lepidocrocite and jarosite. They were not studied in detail."

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4.7 - STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Geochemistry [section to be added, with reference to Bale]

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4.8 - STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Miscellaneous [section to be added, with reference to Bale]

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4.9 - STRATIGRAPHY AND SEDIMENTOLOGY - Lower Barton Clay - Extra [section to be added]

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SECTION 5 - MIDDLE BARTON CLAY - STRATIGRAPHY AND SEDIMENTOLOGY - DETAILS

STRATA: 5. Middle Barton Beds - Barton Clay.

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Barton palaeogeography of the Isle of Wight, New Forest and adjacent area showing the first effects of Tertiary compression, Atlas Phase, from the south

Go to the Alum Bay webpage for details of the Middle Barton pebble Bed with its evidence of early erosion of Upper Greensand Chert.

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See also the Naish Farm Section, as described in the Barton and Highcliffe Coast Erosion and Sea Defences webpage.

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Near the upper nodule horizons are exceptionally-rich fossil beds (Bed E - the Earthy Bed). The top of the Barton Clay is marked by the Stone Band or Shell Band, probably a storm accumulation of shells or some type of shell beach. This is brown and sideritic. It is not always firmly lithified, but often is, producing reddish, hardened slabs, which can be found on the beaches. These reddish slabs are full of Turritella and various bivalves. The Barton Clay of the Middle Barton has yielded remains of a rare cetacean - Basilosaurus , formerly referred to as Zeuglodon wanklyni Seeley, some bones of which together with a fine collection of Barton molluscs are in the building of the Bournemouth Natural Science Society (White, 1917).

5.1 - STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay - General

5.2 - STRATIGRAPHY AND SEDIMENTOLOGY - Middle Barton Clay [ready for additional text]

5.3 SEDIMENTOLOGY - Clay Mineralogy and Aragonitic Shell Preservation -
A notable feature of the Middle Barton Clay is the excellent preservation of aragonitic shells. Most of the fauna is aragonitic, but there are also calcitic oysters (Ostrea) present. Shell colour is not preserved.

5.4 SEDIMENTOLOGY - Geochemistry -
A detailed geochemical study of the Barton Clay has been made by Bale. This includes the Middle Barton Clay. For a brief summary or abstract of this large geochemical thesis go down to section 5.6, a short distance below.

5.5 SEDIMENTOLOGY - Sedimentary Structures, Septarian Nodules (Highcliffe - Barton)
Septarian nodules are important features of the Middle Barton Clay. These are calcitic nodules with internal open fractures. The fracture walls are coated with light-brown sparry calcite. They have almost certainly formed during the Fermentation stage of diagesis.

As discussed elsewhere in this webpage, there are nodules of siderite in the lowest part of the Barton Clay Formation at Hengistbury Head and in the western part of Highcliffe near Friars Cliff (and there is some siderite at the top of the Barton Clay Formation). In the middle Barton Clay, however, nodules of calcite are well-developed. These can be seen at the easily accessible lower cliff, immediately to the east of the Chewton Bunny stream outflow.

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5.6 - STRATIGRAPHY AND SEDIMENTOLOGY - Barton Clay - Clay Mineralogy [repeated from Lower Barton Clay - section 4.6]

Clay mineral data for the Lower Barton Clay has been given by Bale.

[some notes after Bale (1984), p. 26.]
"Gilkes (1966) [Professor Robert Gilkes] undertook [at Southampton University] the investigation of the clay mineralogy of the Palaeogene Beds of the Hampshire Basin, and found the clay mineralogy essentially comprised montmorillonite [now referred to as smectite], illite, kaolinite, traces of chlorite and some undifferentiated mixed-layer phases. In the Upper Eocene sediments, illite and montmorillonite dominated the clay mineralogy, with illite often constituting more than 40 percent of the clay fraction. Kaolinite, however, occurs in very high amounts in the Barton Sand and the 'Lower Headon Beds' at Heatherwood Point and Totland Bay on the Isle of Wight. The clay minerals are believed (Gilkes, 1966; Perrin, 1970) to have been derived from exposed Pre-Tertiar rocks located to the west and north of the basin. Recently, however, Gilkes (1978) re-explained the high illite contents of clay fraction in sediments of the "Lower Headon Beds" and the succeeding Oligocene sediments of the Isle of Wight as re-worked neoformed illites from very nearby sites. The author argued that illite neoformation could have occurred during dry periods within confined water-bodies, such as has been proposed in the Palaeogene sediments of the Paris Basin (Millot, 1970). The other minerals observed by Gilkes (1966) in the clay fraction were quartz, feldspars, anatase, calcite, siderite, goethite , lepidocrocite and jarosite. They were not studied in detail."

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5.7 SEDIMENTOLOGY - Geochemistry of the Barton Clay Formation and Associated Strata

Much has been written about the geochemistry of the Barton Clay and other Upper Eocene sediments. A major reference work is the large and detailed, Ph.D. thesis (1984) of Dr. R.B. Bale, formerly of Southampton University and now on the staff of the University of Ilorin, Kwara State, Western Nigeria (location - north of Lagos). Only the abstract is given here but much important geochemical data on the Upper Eocene of southern England is present in this large thesis; it runs to 483 pages of text before the figures and plates are reached.

Bale, B (Babatunde), 1984. Mineralogical and Geochemical Studies of Upper Eocene Sediments of the Hampshire Basin of Southern England. Doctor of Philosophy Thesis, Geology, Faculty of University of Southampton. [the author was informally known at Southampton University as "Tunde Bale"]
Abstract:
"Sediments of the marine Barton Clay Formation, Barton Sand Formation, and the non-marine 'Lower Headon Beds' exposed along the coastal cliffs on mainland Hampshire and the Isle of Wight have been investigated mineralogically and geochemically.
Sandy-clays and quartz-sand predominate and are dominated by quartz, clays and microcline feldspar with small amounts of anatase, goethite, pyrite, albite, oligoclase, biogenic calcite, aragonite and organic-carbon. The clay assemblage comprises degraded illite, smectite, kaolinite, illite-smectite and traces of chlorite.
Geochemically the sediments are silica-rich but poor in alkali and alkaline-earths. Their trace element contents show strong association with clays and feldspars; while substantial concentrations of As, Ce, Cr, Cu, I, Mn, Pb, Sr, Zn occur with plant remains and/or carbonates. In general, the sediments show no significant facies-related compositional variation nor evidence for substantial diagenetic alteration.
Support is provided for sediment derivation from Cretaceous sediments and intrabasinally-exposed Tertiary sediments of adjoining land areas in England and horst structures in the English Channel. Continuous low-scale tectonic movements and episodic eustatic sea-level fluctuations caused alternating periods of slow, clayey deposition and relatively shorter periods of rapid, sandy sedimentation.
Palaeosols related to red-yellow podzols and hydromorphic swamps have been identified. These contain abundant authigenic kaolinite and goethite. Lepidocrocite, jarosite and gypsum occur in association with the hydromorphic palaeosols, although these are difficult to distinguish from Recent weathering products.
Authigenesis of Fe- and Ca-rich phases was widespread. Freshwater limestones were formed, dominantly composed of micritic low-Mg calcites. Glauconitic-mica formed in the Barton Clay, predominantly within microfossil tests. Its time of formation seems to be substantially less than previously considered likely. Calcian-siderite ironstones and ferroan-calcite septarian concretions formed in early diagenesis at very shallow depths. The siderite shows between 1 and 10 mol percent Ca substitution. The substitution is facies-related, and greatest in marine and 'brackish' sediments. Ferroan calcite occurs in associated with glauconie within marine sediments only. It is believed to form rather than siderite as a result of the early depletion of iron-oxide during glauconitisation. The formation of these low-Mg carbonate phases is highly unusual at shallow depths, and is believed to result from the high influx of iron-oxide and dissolved CaCO3.
The clay assemblage, the red-yellow podzol palaeosolds and the authigenic phases, together, suggest the prevalence of a warm, humid, probably sub-tropical palaeoclimate with moderate-intense weathering and active erosion." [end of the Abstract of Dr. Bale's thesis. Acknowledgements and Contents follows.]

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5.8 SEDIMENTOLOGY - [no contents yet]

5.9 SEDIMENTOLOGY - [no contents yet]

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CONTENTS - SECTION 6 - BECTON SAND GROUP = CHAMA SAND FORMATION AND BECTON SAND FORMATION.
STRATIGRAPHY AND SEDIMENTOLOGY DETAILS

6.1 The Chama Sand Formation of the Barton Group [link working]

(The terminology of Bristow et al. (1991) is used here. Barton Group with Barton Clay Formation, Chama Sand Formation and Becton Sand Formation is used here, instead of the traditional "Barton Clay and Barton Sand" nomenclature)

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The Chama Sand Formation of the Barton Group, seen here as exposed in December 2017, at the foot of the eroding re-entrant at the eastern end of the sea defences of Barton-on-Sea, Hampshire, a view from the beach

The Chama Sand Formation of the Barton Group, formerly known as the Chama Bed, with Chama squamosa

The blue-grey, argillaceous sand of the Chama Sand Formation, Barton Group, in a mid-cliff landslide, at Sea Road Access, Barton-on-Sea, Hampshire, 22nd November 2009

The Chama Sand Formation at Barton-on-Sea, Hampshire, old photograph

The Chama Sand Formation, east of Barton-on-Sea, an old view, close-up

The Eocene bivalve, Chama squamosa, characteristic of the Chama Sand Formation, of the Barton Group

The Chama Sand Formation, Barton Sand Formation, exposed by terminal scour type of coast erosion at the eastern end of the Barton sea-defences Barton-on-Sea, Hampshire, 16th December 2017

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The Chama Sand Formation of the Barton Group, immediately above the Barton Clay, is a shelly, bluish-grey, sandy clay passing up into clayey sand. Chama is correctly pronounced "Kay-ma" because of the Greek origin of the name. The characteristic bivalve Chama squamosa Solander is abundant (squamous, incidently, means scaley, which well describes the appearance of this bivalve). It is sometimes found with paired valves, but, in general, as shown in the photographs, it is present in a death assemblage, a thanatocoenose. Probably there has been little distant transport of these shells, but movement by storms of the argillaceous shoal-sand in which they lived. Chama is a genus ranging from probably Upper Cretaceous to Recent. It is an epifaunal suspension feeder and usually attached. The modern Chama, larger and more spiny than these specimens, is known as a "Jewell Box" and occurs on reefs in Indo-Pacific tropical waters. I do not know whether the Barton Chama was attached, and if so, what to. The palaeolatitude was not tropical; it was about 37 degrees north, about the same as southern Spain, but a little wetter with no significant evaporites (not north of Paris). The temperature was higher than normal in the Eocene, though, so the presence of these tropical shells is not surprising. I wonder if they had some reddish or violet colour to them, like the modern ones.

A interesting aspect of the shells is the extent to which many have been bored by marine organisms. The shells are certainly thick enough to contain many borings, but it is not clear just why the borings are such features here because they are not particularly abundant elsewhere in the Barton strata.

The Chama Sand Formation is now largely, but not entirely, covered by sea-defences of limestone blocks and gravel. It used be a notorious bed for quicksands, water running through the Barton Sands and emerging in this poorly lithified basal unit. Most of the quicksands in the cliff are now covered and drained. It can be a local problem to horse riders in the New Forest, forming small but treacherous, yellow boggy springs on Yew Tree Heath and elsewhere in the eastern Forest. Oxidation of pyrite within it produces chalybeate (iron) springs both in the cliffs and in the New Forest. Notice the "rusting" along a crack in one photograph and the iron-cementation of some flint shingle from the beach on the face of the exposure in another. At Calshot, in the power station outfall tunnel, it is an oyster bed rather than a typical Chama Bed. The blue-green colour of the Chama bed is mostly the result of a content of much glauconite amongst the sand, but there is some variation in appearance according to the extent of oxidation and the proportion of clay present.

Burton (1929; 1933) has discussed the general characteristics and fauna of the Chama Bed. At Barton it is 5.5m (18 feet) thick. The lower part, 3m (10 feet), consists of bluish-grey sandy clay with numerous fossils. The upper part, 2.4m (8 feet), consists of greenish grey or bluish grey, clayey sand with fewer fossils, chiefly bivalves. It is this upper part which is shown here in the photographs, and has relatively few shells apart from Chama. If you look carefully, though, you will notice part of a Turritella. Of all the subdivisions of the Barton Beds, it is the lower part of the Chama Bed which has most foraminifera. Bryozoa are more numerous in this bed than in the Barton Clay beneath. An interesting feature of the Chama Bed, not normally seen now, is the presence of spheroidal concretions from 0.3m to almost a metre in diameter.

Burton (1933) pointed out that molluscs do not occur as thin seams of shells, as in the lower beds, but are distributed throughout the vertical extent of the bed. They can be lost through decalcification. This is seen in the top of the present exposure of the bed, where there are only moulds, and there has been decalcification where the bed is high in the cliff, west of Barton Court. The lower part is characterised by Chama squamosa and Lyria decora and the upper part by 'Meretrix' incurvata and Volutolithes pertusus. The fauna embodies a number of species not occurring in the lower subdivisions at Barton. Common Lower Barton species, absent in the Middle Barton, but reappearing in the Chama Bed are: Calliostoma nodulosum and Tornatellaea simulata . For more information on the fauna see Burton's (1933) faunal list for Bed H in his section VII. The bed is also exposed at Alum Bay and Whitecliff Bay; it is of broadly similar thickness and is very fossiliferous at both localities (White, 1921)

The Chama Bed can be regarded as a marker of a significant local change in enviroment about 40 million years ago. According to Murray and Wright (1974) the Barton Clay beneath is of shelf regime until the Chama Bed indicates marked shoaling. There was a silting-up of the sea, heralding the lagoonal and freshwater conditions of the Headon Hill Formation which were to follow in a while.

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6.2 The Becton Sand Formation [update 19.11. 2018, link working]

The Becton Sand Formation (originally referred to as part of the "Barton Sands" or Becton Bunny Beds) is 23.2m. in thickness. The lowest third (8 metres) of sands is unfossilfierous. The grey-brown clays in the middle part contain both marine shells (Olivella, Pollia, Nucula and Pitar) and estuarine shells (Potamides, Corbicula and Bayania). The progressive uplift of the Isle of Wight Chalk stuctures was taking place, and there was now some restriction of sea-water coming into the area from the east (southern sea water access had already been closed). If earthquakes were taking place then, as was likely, they have not left the major effects, like those so obvious in the Eocene at Hengistbury Head.

Above the Chama Sand Formation comes the Becton Sand Formation. At the base (i.e. just above the Chama Sand Formation) are light-coloured unfossiliferous sands overlain by "earthy" sands. There follows dark sandy clay with the brackish water bivalve - Oliva branderi J. Sowerby. Next there is sandy loam with brackish water shells such as Cyrena, Dreissensia, Erodona etc. (White, 1917). Finally the white and yellow sands of the Long Mead End Beds contain Lucina gibbosula Lam., Batillaria pleurotomoides Lam. etc and are terminated by a thin band of greenish clay at the junction with the Headon Hill Formation ("Headon Beds" in the old literature). The Becton Sands shows evidence of shoaling water conditions and a progressive change towards the lagoonal and lacustrine environments of the Headon Hill Formation (with Swamp-Cypress trees and crocodiles.

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7.2 EOCENE - MECO - Middle Eocene Climatic Optimum

INTRODUCTION continued - Barton Clay - MECO

[Introductory comments from Wikipedia} "Another event during the middle Eocene that was a sudden and temporary reversal of the cooling conditions was the Middle Eocene Climatic Optimum. At around 41.5 million years ago, stable isotopic analysis of samples from Southern Ocean drilling sites indicated a warming event for 600 thousand years. A sharp increase in atmospheric carbon dioxide was observed with a maximum of 4000 ppm: the highest amount of atmospheric carbon dioxide detected during the Eocene. The main hypothesis for such a radical transition was due to the continental drift and collision of the India continent with the Asia continent and the resulting formation of the Himalayas. Another hypothesis involves extensive sea floor rifting and metamorphic decarbonation reactions releasing considerable amounts of carbon dioxide to the atmosphere."

The Bartonian Stage is reported in the Geologic Time Scale [2012 edition] to have lasted from 41.2 to 37.8 million years (with the Priabonian from 37.8 to 33.9 million years. There may be revisions to these dates but changes are not likely to be large. The implication of these dates is that at least part of the Barton Clay Formation was deposited in particularly warm water conditions. This may account, at least in part, for the very rich shelly fauna of the Barton Clay.

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8. Pleistocene Strata  

8.1 Pleistocene Gravel (Plateau Gravel)

Plateau Gravel 0 - 2.1m
1.5 - 7.6m.
8.2 Brickearth

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SECTION 8 - PALAEONTOLOGY - FOSSILS

8.1 FOSSILS FROM THE BARTON CLAY - Introduction

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The fossil Turritella, auger shells of the Eocene Barton Clay Formation at Barton-on-Sea, Hampshire, southern England

The gastropod Turritella is abundant in parts of the Barton Clay and is usually easy to find in the cliffs of Barton and Highcliff. Above is shown a photograph of abundant Turritella sulcifera on an Eocene beach.

The common gastropod fossil, Athleta athleta, formerly known as Voluta or Volutaspina, from the Eocene Barton Clay Formation at Barton-on-Sea, Hampshire, southern England

When searching the Barton and Highcliffe cliffs in the 1950s, it was fairly easy to find good specimens of the medium-sized gastropod, Athleta, or "Voluta" as it was known to collectors then. It is a typical, medium-sized fossil of the Middle Barton Clay. Specimens can still be found, although they are more likely to be broken, rather than perfect.

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[Fossil Shark's teeth of the Barton Cliffs]

Finding sharks' teeth washed out of the Barton Clay between Highcliffe and Barton-on-Sea, Hampshire, 24 November 2007

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Stratiolamia macrota a common fossil shark's tooth of the Eocene Barton Clay at Barton-on-Sea, Highcliffe and Hengistbury Head, Hampshire and Dorset, southern England

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Tooth of the Eagle Ray - Myliobatis, washed out of the Barton Clay and found on the beach between Highcliffe and Barton-on-Sea, Hampshire

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An Eocene shark's tooth from the Barton Clay, as found in 2001, washed out on the low-tide beach sand about 150 metres east of Chewton Bunny outlet, Highcliffe

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A shark's tooth from the Eocene, Barton Clay, found in 2001, east of the Chewton Bunny outlet, Highcliffe

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[[8 contin] Fossil Bivalves and Gastropds of the Barton Cliffs]

The two large fossil gastropods, Clavilithes macrospira and Clavilithes longaevus, that are occasionally found in the Eocene, Barton Clay of Highcliffe and Barton-on-Sea, Hampshire, southern England

Finding a small specimen of the fossil gastropod, Athleta in the Barton Clay of the lowest part of the sea cliff between Highcliffe and Barton-on-Sea, Hampshire, southern England

A small specimen of the common fossil bivalve, Crassatella sulcata that I have just found in the Barton Clay between Highcliffe and Barton-on-Sea, Hampshire, southern England

Lowry's figure, upper part, of Barton fossils, larger version with some details clarified or emphasised

Lowry's figure, lower part, of mainly Bracklesham fossils, larger version

Some selected fossil bivalves from the Barton Clay Formation, two species of which occur at Hengistbury Head, in addition to occurrence at Barton and Highcliffe

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The scaphopod Dentalium or Anatalis which is very common in  the Barton Clay Formation of Barton and Highcliffe

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Barton Fossils of the Morton Collection [For excellent photographs of Barton and other Eocene and also Oligocene fossils go to the impressive website of Alan Morton:

A Collection of Eocene and Oligocene Fossils
"This Web Site displays more than 2,000 of the characteristic fossils of the Eocene and Oligocene deposits of England. It is hoped that this provides a useful resource for those wishing to identify their own fossils. Comments and suggestions about the content of this Web Site are welcomed, including any suggested corrections or additions to the naming of the illustrated species. The images on this website are Copyright of Alan Morton. If you would like to seek permission to use any of the images for your own purposes, contact Alan Morton and describe your proposed usage."]

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Barton Fossils of the Dent Collection

Bournemouth Natural Science Society of 39 Christchurch Road, Bournemouth, Dorset, BH1 3NS (telephone 01202-394534) has a large collection of fossils from the nearby coast of Barton and Highcliffe. The following notes are from Sir Daniel Morris in 1914:

"An important event in the history of the society has been the acquisition of the Dent Collection of Barton fossils. This collection was brought together many years ago by the late Mr. Dent of Barton Court, and his father who were owners of the cliffs. Good facilities were then afforded for collecting Barton fossils; but owing to the fall and washing away of these cliffs these facilities have long ceased to exist. Living close by, Mr. Dent and his father were successful in bringing together a collection which has long been regarded as of special value. It was described by Mr. Henry Keeping, curator of the museum at Cambridge, as 'one of the best in the world - probably only equalled by the Edwards Collection in the British Museum and the one in the Sedgwick Museum at Cambridge.' Before the collection was purchased it was carefully examined in behalf of the society by an expert from the British Museum, who reported: 'All the fossils are in a fine state of preservation, and such a series will probably never be obtained again'. There are 800 specimens of vertebrate animals and 3,375 fossil shells. Some of the latter are of exceptional interest. There are several specimens of the rarer species showing variations; also the gradual changes in development from the young to the adult stage. Of some species there are more than 100 specimens.
Perhaps the most interesting fossils in the Dent Collection, amongst the vertebrates, are the bones of an extinct whale-like animal - the Basilosaurus formerly referred to as Zeuglodon (but this is a junior synonym). Such remains are said to be uncommon in museum collections in this country. The British Museum possesses [in 1914] no portions of this animal from the Barton beds."

The present writer, can certainly confirm the quality of this collection. I have seen it recently, but remember the initial impression back in my school-days given by the fine Clavilithes longaevus and the fan-shell Hippochrenes amplus, amongst many others.

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[8 contin] BARTON FOSSILS

Burton's Listing - Introduction.

See the classic papers by St.John Burton (1925; 1929; 1931 and 1933). Mr. St.John (pronounced "Syngen") Burton, lived in a bungalow on the cliff top at Barton-on-Sea and collected regularly in a very systematic way from the various divisions of the Barton Clay Formation and Becton Sand Formation (then the "Barton Sand"). [I only met him once and that was in the 1950s at Bournemouth Natural Science Society]. He had divided the sequence of the Barton Clay into a series of lettered beds, A to F, and the Barton Sand into horizons G (the Shell Bed or Stone Band) up to L. There have been some later terminological changes with regard to the Becton Sand, but his units are easily understood. The divisions of the Barton Clay are not overall so easily recognised now (except for certain parts, such as Horizon C and D) because of the combination of sea defences, rock armour, artificially-deposited gravel and, as always, frequent landslides. The "Horizons" of Burton and other aspects of the Barton cliffs are discussed elsewhere in this webpage and in associated webpages on coast erosion and landslides at Barton and Highcliffe:
Barton and Highcliffe - Coast Erosion and Landslides.
Barton Erosion History

Burton, E. St.J. 1933. Faunal horizons of the Barton Beds of Hampshire. Proceedings of the Geologist's Association, vol. 44, Part 2, pp 131-167. This classic paper on the fossils of Barton-on-Sea with a large and important faunal list. Since the paper was published in 1933, some of the faunal names have changed, but the old names are usually easily recognised. A version of the list is reproduced below.

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8.1a LIST OF BARTON FOSSILS - by E. St. John Burton, 1933

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Mr Edward St.John Burton made a superb collection of Barton Clay fossils and some papers on the subject. He was a very enthusiastic and very successful amateur palaeontologist and collector who wrote some key papers on Barton fossils and stratigraphy (and also collected superb material from the Bracklesham strata during the excavation the Southampton Dry Dock). At time that St.John Burton was collecting at there no sea defences on any scale the cliff was eroding steadily. In one of his papers he gave a complete list of Barton Fossils (known at that date). He also discussed some inland exposures of Barton strata.

A simplified version of the 1933 list of fossils known from the Barton Clay Formation and the Becton Sand Formation ("Barton Sand") is given here. It is complete copy of Burton's list as a sequence of names, but it does not show the abundance in particular beds. The full list in the following, easily accessible paper by Burton and this should be read.
Burton, E. St. J. 1933. Faunal horizons of the Barton Beds of Hampshire. Proceedings of the Geologist's Association, vol. 44, Part 2, pp 131-167. See Burton, E. St. J. 1933. Faunal horizons of the Barton Beds of Hampshire. Proc. Geologists' Assoc., vol. 44, Part 2, pp 131-167.

At the time when Burton was collecting the Barton Clay cliffs were very much better exposed and less searched by the public. The cliffs had not then been affected by the modern increase in plant growth that is a familiar consequence of global warming. Since then some parts have been much obscured by sea-defences and some of these fossils will be difficult or impossible to find. There are also more visitors and more collectors now.

The species names are given in their original form and the genera have not been updated. The original charts given in Burton's paper should be consulted, though, if bed by bed information is needed. This is not given here. He listed the frequency of occurrence of each of these species within the Barton units A1, A2, B, C, etc up to Bed K in the Becton Sands. He stated whether the species was "Very Common, Common, Frequent, Not Common, Rare, Very Rare or not found. It would be too time-consuming the retype this data in the version of the list below. The reason that the species list has reproduced here in text format is that it is now searchable by computer. Regard this list as only an introduction and if possible follow up new fossil data from current literature.

[NB. The fossils in the list are from the Barton Clay and Barton Sand of the Barton-on-Sea and Highcliffe cliffs, and not from equivalent strata (i.e. Lower Barton) at Hengistbury Head. For Hengistbury fossils see my webpage:
Hengistbury Head Geology.]




8.1 BARTON FOSSIL LIST OF ST.JOHN BURTON (WITHOUT ABUNDANCE).

PLANTAE (List of St. John Burton, 1933)

[This list is very limited regarding plants. See the later work of Chandler (1960) for more information on this subject.]

Endocarp (allied to Mastixia (rare in A3 only)
Pityostrobus dixoni (Bowerbank)
Sequoia sp. [tree, new at that date to the Bartonian of England]
Wood fragments and rhizomes.

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FORAMINIFERA (List of St. John Burton, 1933)

Anomalina ammonoides (Reuss)
Anomalina grosserugosa (Gumbel)
Cornuspira carinata (da Costa)
Cornuspira involvens Reuss
Cristellaria cultrata Montfort
Cristellaria inornata d'Orbigny
Cristellaria rotulata Lamarck
Miliolina ferussaci (d'Orbigny)
Miliolina seminulum (Linne)
Nebecularia sp.
Nodosaria badenensis d'Orbigny
Nummulites elegans J. de C. Sowerby
Polymorphina acuminata (d'Orbigny)
Pullenia sphaeroides (d'Orbigny)
Ramulina sp.
Truncatulina lobatula (Walker and Jacob)
Truncatulina refulgens Monfort

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HYDROZOA (List of St. John Burton, 1933)

Axopora michelini Duncan
Holaraea parisiensis (Michelin)

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ANTHOZOA (List of St. John Burton, 1933)

Graphularia wetherelli Milne-Edwards
Madrepora solanderi Defrance
Oculina cf. conferta Edwards and Haime
Paracyathus crassus Edwards and Haime
Turbinolia affinis Duncan
Turbinolia bowerbanki Edwards and Haime
Turbinolia firma Edwards and Haime
Turbinolia forbesi Duncan
Turbinolia frediciana Edwards and Haime
Turbinolia humilis Edwards and Haime
Turbinolia sp. nov.

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ECHINODERMATA (List of St. John Burton, 1933)

Cidaris websteriana Forbes
"Echinus" dixoni Forbes
Echinopedina edwardsi (Forbes)
Hemiaster branderi Forbes
Maretia grigonensis (Desmaret) (= Spatangus omalii Forbes
Ohioglypha sp.

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BRYOZOA (POLYZOA) (List of St. John Burton, 1933)

?Aimulosia spp.
Biselenaria offa Gregory
Conopeum buski (Gregory)
Conopeum crassomurale (Gregory)
Conopeum sp.
Heterocella sp.
?Hippoporina sp.
Hornera sp.
Lichenopora gregoryi Canu
Lunulites transiens Gregory
Membranipora sp. nov.
Micropora cribiformis Gregory
Mucronella augustooecium Gregory
Nellia sp.
Onychocella sp. nov.
Peristomella sp. nov.
Puellina sp.
Pyripora sp.
Srupocellaria sp.
Sphaeropora [Heteropora] glandiformis (Gregory)
Sphaeropora [Heteropora] glandiformis (Gregory) variety
Teichopora (Bracebridgia) clavata Gregory
Tryposta sp.
Umbonella bartonensis Gregory

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BRACHIOPODA (List of St. John Burton, 1933)

Terebratula sp. nov

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ANNELIDA (List of St. John Burton, 1933)

Ditrupa plana J. Sowerby
Serpula crassa J. de C. Sowerby
Serpula cf. exigua J. de C. Sowerby
Serpula extensa Solander
Serpula cf. flagelliformis J. de C. Sowerby
Serpula heptagona J. de C. Sowerby

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CRUSTACEA (List of St. John Burton, 1933)

(Ostracoda)

Bairdia contracta Jones
Cythere consobrina Jones
Cythere costellata (Romer)
Cythere plicatula Munster
Cythere scrobiculoplicatula Jones
Cythere striatopunctata Jones
Cythere wetherelli Jones
Cythereis horrescens Jones
Cytherella muensteri (Romer)
Cytheridea debilis Jones
Cytheridea muelleri (Munster)
Cytheridea perforata (Romer)
Krithe bartonensis (Jones)

(Cirripedia)

Balanus unguiformis J. de C. Sowerby var erisma Darwin

(Malacostraca)

Callapa sp.

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MOLLUSCA - BIVALVIA)(List of St. John Burton, 1933)

Amussium corneum (J. Sowerby)
Anadara globulosa (Deshayes)
Anomia tenuistriata Deshayes
Anomia sp
Arca biangula Lamarck
Barbatia appendicalata (J. Sowerby)
Bicorbula gallica (Lamarck)
Bicorbula sp. nov
Callista aff. laevigata (Lamarck)
Callista suberycinoides (Deshayes)
Callista transversa (J. de C. Sowerby)
Callocardia aff nitidula (Lamarck)
Chama squamosa Solander
Chama turgidula Lamarck
Chama sp.
Chlamys carinata (J. de C. Sowerby)
Chlamys recondita (Solander)
Chlamys tumescens (Edwards MS)
Clavagella coronatum Deshayes
Corbula cf costata (J. de C. Sowerby)
Corbula cuspidata J. Sowerby
Corbula ficus (Solander)
Corbula globosa J. Sowerby
Corbula cf. lamarcki Deshayes
Corbula pisum J. Sowerby
Corbula rugosa Lamarck
Crassatellites bronni (Merian MS)
Crassatellites grignonensis (Deshayes)
Crassatellites var anglica S.V. Wood
Crassatellites pumilio S.V. Wood
Crassatellites subquadratus (S.V. Wood)
Crassatellites sulcatus (Solander)
Crassatellites sulcatus var ensiformis (Edwards MS) S.V. Wood
Crassatellites tenuisulcatus (Edwards MS)
Cultellus affinis (J. de C. Sowerby; S.V. Wood)
Cyrena gibbulosa Morris
Cyrena deperdita Deshayes
Divaricella colvellensis (Edwards MS)
Divaricella rigaultiana (Deshayes)
Fossularca lissa (Bayan) (= F. laevigata Caillat non Spengler)
Gari compressa (J. de C. Sowerby)
Gari rudis (Lamarck)
Gastrochaena ampullaria (Lamarck)
Glycimeris deleta (Solander)
Glycimeris proxima (S.V. Wood)
"Leda" minima (J. Sowerby)
Lentidium nitidum (J. Sowerby)
Lima cf. sorar S.V. Wood
Limopsis scalaris J. de C. Sowerby
Lithodomus sp.
Loxocardium obliquum (Lamarck)
Lucina cf concentrica Lamarck
Lucina (Cavilucina) elegans Defrance
Lucina (Gibbolucina) gibbosula Lamarck
Lucina spinulosa Edwards
Lutetia parisiensis (Deshayes)
Mactra compressa Deshayes
Martesia spp.
"Meretrix" gravida (Edwards MS)
Meretrix incurva (Edwards)
Meretrix trigonula (Deshayes)
Modiola cf. dimidiata S.V. Wood
Modiolaria seminuda (Deshayes)
Mytilus affinis J. de C. Sowerby
Mytilus strigillatus S.V. Wood
Nemocardium parile (Deshayes)
Nucula ampla S.V. Wood
Nucula bisulcata J. de C. Sowerby
Nucula praelonga (Edwards MS)(S.V. Wood)
Nucula similis J. Sowerby
Nucula tumescens (Edwards MS) S.V. Wood
Ostrea dorsata Deshayes
Ostrea plicata (Solander)
Ostrea gigantea J. Sowerby
Ostrea cf. tenera J. Sowerby
Panopea corrugata J. Sowerby
Pholadomya margaritacea J. Sowerby
Pitaria sp.
Pteria [Avicula] media J. de C. Sowerby
"Solen" sp.
Sportella sp.
Sunetta branderi (Edwards MS)
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"Tellina" ambigua J. de C. Sowerby
Tellina filosa J. de C. Sowerby
Tellina hantoniensis Edwards
Tellina (Eoelliptica) tellinella Lamarck
Tellina sp.
Terodo sp.
Tivelina elegans (Lamarck)
Tivelina solandri (J. Sowerby)
Trachycardium porulosum (Solander)
Trinacria deltoidea (Lamarck)
Venericardia corpuluscum S.V. Wood
Venericardia cf. crebisulcata (Edwards M.S.) (S.V. Wood)
Venericardia davidsoni (Deshayes)
Venericardia oblonga J. Sowerby
Venericardia simplex (S.V. Wood)
Venericardia sulcata (Solander)
Venericardia trapezoidalis (S.V. Wood)
Veniella pectinifera (J. de C. Sowerby)
Woodia crenulata (Deshayes)

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SCAPHOPODA(List of St. John Burton, 1933)

Dentalium (Laevidentalium) acicular Deshayes
Dentalium striatum Sowerby

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GASTROPODA (List of St. John Burton, 1933)

Acera striatella (Lamarck)
Acteon cf. gardneri Cossman
Acteon sp.
Acteon sp.
Acteonida elongata (J. de C. Sowerby)
Adeorbis politus (Edwards M.S.) Morlet
Adeorbis sp.
Adeorbis sp.
Admete (Bonellitia) evulsa (Solander)
Admete (Bonellitia) evulsa var. producta (Edwards M.S.)
Admete (Bonellitia) nitens (Beyrich)
Admete (Comptostoma) quadrata (J. Sowerby)
Ampullela mutabilis (Solander)
Ampullela cf. parisiensis (d'Orbigny)
Ancilla aveniformis J. Sowerby
Ancilla buccinoides Lamarck
Ancilla (Tortoliva) canalifera Lamarck
Ancilla dubia (Deshayes)
Ancilla obesa Edwards M.S.
Aporrhais c.f. sowerbyi (Mantell)
Asthenotoma biconus (Edwards)
Asthenotoma conoides (Solander)
Asthenotoma dissimilis (Edwards)
Asthenotoma helicoides (Edwards)
Asthenotoma microcheila (Edwards)
Asthenotoma pupa (Edwards)
Asthenotoma zonulata (Edwards)
Bartonia caniculata (J. de C. Sowerby)
Bathytoma aff. granata (J. de C. Sowerby)
Bathytoma hemileia (Edwards)
Bathytoma turbida (Solander)
Batillaria cf. calcitrapoides (Lamarck)
Batillaria pleurotomoides (Lamarck)
Bayania hordacea (Lamarck)
Bela juncea (Solander)
Bittium semigranulosum (Lamarck)
Bittium terebrale (Lamarck)
Bornsonia lineata Edwards
Bornsonia semicostata Edwards
Bullinella acuminata (J. Sowerby)
Bullinella angystoma (Deshayes)
Bullinella constricta (J. de C. Sowerby)
Bullinella elliptica (J. de C. Sowerby_
Bullinella sp.
Calliostoma nodulosum (Solander)
Calyptraea aperta (Solander)
Cappulus penatus (Lamarck)
Capulus squamaeformis (Lamarck)
"Cassidaria" nodosa (Solander)
Cerithioderma costellatum (Edwards M.S.)
"Cerithium" sp.
Clavatula desmia (Edwards)
Clavilithes cylindricus Wrigley
Clavilithes elongatus (Edwards M.S.) Wrigley
Clavilithes longaevus Solander
Clavilithes macrospira Cossman
Clavilithes scalaris (Lamarck(
Clavilithes sp. indet.
Cominella deserta (Solander)
Cominella sp.
Conomitra parva (J. de C. Sowerby)
Conomitra parva var pumila (J. de C. Sowerby)
Conomitra porrecta (Edwards)
Conorbis alatus (Edwards)
Conorbis dormitor (Solander)
Conus (Hemiconus) lineatus Solander
Conus (Hemiconus) scrabriculatus Solander
Cornulina minax (Solander)
Cryptoconus priscus (Solander)
Cryptospira pusilla (Edwards)
Crypstospira simplex (Edwards)
Cypraea (Bernaya) bartonensis Edwards
Dientomochilus bartonensis (J. Sowerby)
Drillia bracheia (Edwards)
Drillia coarctata (Edwards)
Drillia constricta (Edwards)
Drillia gomphoidea (Edwards)
Drillia granulata (Lamarck)
Drillia innexa (Solander)
Drillia scrabiuscula (Edwards)
Drillia verticillum (Edwards)
Drillia sp. indet.
Eopleurotoma cedilla (Edwards)
Europleurotoma lima (Edwards)
Europleurotoma monerma (Exwards)
Europleurotoma puella (Edwards)
Europleurotoma rotella (Edwards)
"Epitonium" acutum (J. Sowerby)
Epitonium interruptum (J. de C. Sowerby)
Epitonium reticulum (Solander)
Epitonium cf, sculptatum (Deshayes)
Epitonium undosum (J. de Sowerby)
Epitonium sp.
Eulima deshayesi (Cossman)
Eulima macrostoma (Charlesworth M.S.)
Eulima polygyra (Charlesworth M.S.)
Eulima sorocula Edwards M.S.
Eulima sp.
Euthriofusus carinella (J. Sowerby)
Euthriofusus lima (J. de C. Sowerby)
Euthriofusus regularis (J. Sowerby)
Euthriofusus sp. nov.
Faunus rigidus (Solander)
Ficus greenwoodi (J. de C. Sowerby)
Ficus nexilis (Solander)
Ficus sindonata Wrigley
Fusinus acuminatus (J. de C. Sowerby)
Fusinus asper (J. de C. Sowerby)
Fusinus porrectus (Solander)
Globularia grossa (Deshayes)
Globularia patella (Lamarck)
Globularia sigaretina (Lamarck)
Globularia sphaerica (Deshayes)
Hemipleurotoma aspera (Edwards)
Hemipleurotoma callifera (Edwards)
Hemipleurotoma denticula (Basterot)
Hemipleurotoma denticula var. conulus Edwards
Hemipleurotoma denticula var. mutica Edwards
Hemipleurotoma gentilis (Edwards)
Hemipleurotoma reticulosa (Edwards)
Hemipleurotoma varians (Edwards)
Hippochrenes amplus (Solander)
Homalaxis sp.
Lacuna sp.
Lyria costata (Solander)
Lyria decorata (Beyrich) (= Voluta maga Edwards)
Marginella bifodo-plicata (Charlesworth)
Marginella gracilis Edwards
Mathildia bourdoti de Boury
Melanopsis cf. fusiformis J. Sowerby
Melanopsis cf. subfusiformis Morris
"Mitra" marginata Lamarck
Mitra (Mitreola) scabra (J. de C. Sowerby)
"Mitra" volutiformis Edwards
Murex albionis Wrigley
Murex bispinosus J. de C. Sowerby
Murex defossus (Pilkington)
Murex defossus var. lineata (Edwards M.S.)
Murex frondosus Lamarck
Murex tricarinatus Lamarck (= Murex asper Solander)
Murex tripteroides Lamarck
"Nassa" obtusa Edwards M.S.
Nassa caillati Deshayes
Nassa epiglottina Lamarck
Nassa sp.
Nassa (Ampullonatica) ambulacrum (J. Sowerby)
Nassa (Polinices) hantoniensis (Pilkington)
Nassa (Euspira) labellata Lamarck
Obeliscus canaliculatus Edwards M.S.
Obeliscus excavatus Edwards M.S.
Obeliscus c.f. polygyrus Edwards M.S.
Odostomia aligata Lamarck
Odostomia hordeola Lamarck
Odostomia sp.
Olivella branderi (J. Sowerby)
Olivella salisburiana (J. Sowerby)
Orthochetus sp. nov. aff. charlesworthi
Paludestrina sp.
Pirena vulcanica (Schlotheim)
Pollia (Tritonidea)lavata (Solander)
Potamides cf. variabilis (Deshayes)
Potamides vagus (Solander)
Pseudoneptunea sindonata (Edwards M.S.)
Ptychatractus interruptus (Pilkington)
Pyrazus angulatus (Solander)
?Rhaphitoma acuticosta (Nyst)
Rhaphitoma plicata (Lamarck)
Rimella rimosa (Solander)
Ringicula parva (Charlesworth MS.) R.B. Newton
Rissoa (Alvania) bartonensis (Charlesworth MS.)
Rissoa (Alvania) globulus Edwards MS.
Rissoa nana (Lamarck)
Rissoa sp.
Rissoina raincourti Cossman
Rostellaria excelsa Giebel
Roxania aff. coronata (Lamarck)
Sassia arguta (Solander)
Sassia flandrica (de Koninck)
Sassia websteri Wrigley
Scaphander sp.
Semicassis ambigua (Solander)
Seraphs fusiformis (Lamarck)
Seraphs sopitus (Solander)
Serpulorbis cancellatus Deshayes
Sinum clathratum (Gmelin)
Solariaxis caniculatus (Lamarck)
Solarium plicatum (Lamarck)
Strebloceras cornuoides Carpenter
Strepsidua turgida (Solander)
Stylifer cf. inserta Edwards MS.
Suessionia [Phos] coartata (Edwards)
Surcula crassicostata (Edwards)
Surcula extorta (Solander)
Surcula aff. inarata (J. de C. Sowerby)
Surcula laevigata (Edwards)
Surcula laneolata (Edwards)
Surcula macilenta (Solander)
Surcula microdonta (Edwards)
Surcula rostrata (Solander) var. antiqua Edwards
Surculites errans (Solander)
Sveltella microstoma (Charlesworth MS.) R.B. Newton
Sycostoma bulbeforme (Lamarck)
Sycostoma bulbus (Solander)
Sycostoma pyrus (Solander) [very common in D and G]
Teinostoma dubium (Lamarck)
Terebra cf. plicatula
Theodoxis sp.
Theodoxis sp.
Theodoxis sp.
Tornatellaea simulata (Solander)
Trivia platystoma Edwards
Turbo sulcata (Pilkington)
Turbonilla costata (J. Sowerby)
Turbonilla costellata Edwards MS.
Turbonilla pulchra Deshayes
Turbonilla cf. scalaroides Deshayes
Turritella edita (Solander)
Turritella imbricateria Lamarck [very common in E]
Turritella sp.
Turritella sp.
Turritella sp.
Typhis parisiensis d'Orbigny (= T. fistulosis J. Sowerby non Brocchi
Typhis pungens Solander
Uxia elongata (Nyst)
Uxia nassaeformis (S.V. Wood MS.) Wrigley
Volutilithes pertusus Swainson [= Voluta humerosa Edwards]
Volutocorbis scabriculus (Solander)
Volutospina ambigua (Solander) [very common in A3 and E]
Volutospina ambigua var.flexicostata (Edwards MS.)
Volutospina athleta (Solander) [Athleta (Volutospina) athleta (Solander) - common in B]
Volutospina athleta var. brevi-spina (Edwards MS.)
Volutospina athleta brevi-spina fortis Edwards
Volutospina depauperata (J. de C. Sowerby)
Volutospina lucta rix (Solander) [very common in E][this is the large Athleta (Volutospina) luctator (Solander), a well-known Barton fossil]
Volutospina lucta rix var. bi-spina
Volutospina nodosa (J. de C. Sowerby)
Volutospina scalaris (J. de C. Sowerby)
Volutospina solandri (Edwards)
Volutospina suspensa (Solander)
Volutospina sp.
Volvaria acutiuscula J. Sowerby
Volvulella lanceolata (J. de C. Sowerby)
Xenophora agglutinans (Lamarck) [small conical shell, very common in E]
Xenophora discoidea (J. Sowerby)
[end of list of gastropods]

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CEPHALOPODA (List of St. John Burton, 1933)

Belosepia sepiodea (Blainville) [distribution not known]
Nautilus sp. indet [occurs in places, not common to rare]
[end of list of cephalopods]

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VERTEBRATA - PISCES [fish] (List of St. John Burton, 1933)

Aetobatis sp.
Apriodon woodwardi
Arius egertoni (Dixon)
Carcharodon auriculatus Blainville [shark, very rare]
Cybium bartonense A. S. Woodward [rare]
Cylindracanthus rectus Egerton
Edaphodon? leptognathus Agassiz
Eugaleus minor Agassiz
? Galeocerdo sp.
Lamna obliqua (Agassiz) [syn Otodus obliquus - shark's tooth]
Lamna vincenti (Winkler)
Lepidosteus sp.
Mioliobatis dixoni Agassiz [frequent - Myliobatis - ray fish teeth]
Mioliobatis tolicapicus Agassiz [Myliobatis]
Mioliobatis sp. indet.
Notidanus primigenius Agassiz
Odontaspis acutissima (Agassiz)
Odontaspis cuspidata (Agassiz)
Odontaspis macrota (Agassiz) [Frequent - a usual Barton shark's tooth]
Odontaspis trigonalis (Jackel)

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(PISCES - FISH CONTINUED - OTOLITHS - Otolithus)
[The reporting by St. John Burton of 37 species of otoliths (ear-stones of fishes) is based on a large series of specimens collected by Rev. W.H. Webster, B.A. of Barton-on-Sea. See the extensive later work on Barton otoliths by Fred Stinton:
Stinton, F. 1974 to 1980. Fish Otoliths from the English Eocene, Palaeontographical Society.]

Otolithus (Apogonidarum) bouryi Priem [presumably an otolith - ear stone of a fish]
Otolithus bouryi duplex Shepherd
Otolithus (Arius) crassus Koken
Otolithus (Arius) sp.B, E.T. Newton
Otolithus (Arius) sp.C, E.T. Newton
Otolithus (Arius) cf. danicus Koken
Otolithus (Arius) parvus Schubert
Otolithus (Berycidarum) bartonensis Schubert
Otolithus (Brotulidarium) rzehaki Schubert
Otolithus (Cepola) praerubescens Schubert
Otolithus (Clupeidarum) cf. testis Koken
Otolithus (Dentax) nobilis Koken
Otolithus (Dentax) aff. subnobilis Schubert
Otolithus (Elops) sp.
Otolithus (Gadus) praeluscus Shepherd
Otolithus (Macrurus) aff. gracilis Schubert
Otolithus (Merluccius)shephardi Schubert
Otolithus (Monocetris) lemoinei Priem
Otolithus (Ophidiidarum) cf. acutangula Koken
Otolithus (Ophidiidarum) dimidiatus Schubert
Otolithus (Ophidiidarum) sp.
Otolithus (Ophidiidarum) subregularis Schubert
Otolithus (Ophidiidarum) waltoni Schubert
Otolithus (Ophidium) pantanelli Basoli
Otolithus [----] sp. nov.
Otolithus Percidarium aff. plebeius Koken
Otolithus (Phycis) bartonensis Schubert
Otolithus (Platessa) sector Koken
Otolithus (Pleuronectidarum) accuminatus Koken
Ottolithus (Psetta) praemaximus Shepherd
Otolithus (Sciaenidarum) insignis Koken
Otolithus (Serranus) bartonensis Priem
Otolithus (Serranus) concavus Priem
Otolithus (Solea) approximatus Koken
Otolithus (Sparidarum) gregarius Koken
Otolithus (Trachinus) mutabilis Koken
Otolithus (insertae sedis) umbonatus Koken [otolith]

[end of otolith section - continues with more sharks and ray fish etc.]

Physodon secundus Winkler [Physodon is a shark belonging to the Carcharidiidae, - Carcharias. The genus is known from the Eocene of the United Kingdom, the United States and Namibia.]
Pristis bisulcatus Agassiz [sawfish]
Scyliorhinus minutissimus (Winkler) [small tooth of shark?]
Squatina cf. crassus Daimeries
Triodon cf. antiquus Leriche
Tubercles of a ray-fish
Vertebrae of fish

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REPTILEA (List of St. John Burton, 1933)

? Argochelys sp.

Crocodilus [Is this the specimen at Bournemouth Nat. Sci. Society? Compare to the well-kown, Hordle Cliff alligator (or "Hampshire Crocodile"), Headon Hill Formation, Diplocynodon hantoniensis . (I have no information as to whether it is the same.)]

Palaeophis [very rare in A3] [a marine snake also known from the Lower Eocene] [end of original list. The following item was listed by St.John Burton, but further notes have been added.]

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7.2 FOSSILS - Introduction

7.3 FOSSILS - Introduction

7.4 FOSSILS - Introduction

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7.5 FOSSIL WHALES

The Archaeocetes or primitive whales, first appeared in the Middle Eocene. Bones of early cetaceans are occasionally found in the Upper Eocene strata of Barton-on-Sea, and at some New Forest localities. These early whales were slim and elongate, up to 21 m. in length, and probably in appearance like that of the fabled "sea serpent". ( Romer,1945). They are well-known from other localities in the world. In Egypt the "Whales Valley" (Wadi Al-Hitan) is a notable UNESCO site for complete skeletons of Eocene whales.

An Eocene Sea Serpent, actually an early whale or Cetacean, Basilosaurus or Zeuglodon, from the Barton Clay of Barton-on-Sea, Hampshire, shown as theoretically complete skeleton and also a tentative reconstruction, with animal colour unknown

An Eocene whale or cetacean, broadly similar to those from the Eocene of Barton-on-Sea, Hampshire, England and the nearby New Forest, from an Egyptian desert and on display in a museum

A cervical vertebra of the early cetacean, or whale, Zygorhiza from the Barton Clay of Barton-on-Sea, Hampshire, described by Andrews in 1907

The occurrences in Hampshire suggest that these early whales could penetrate into very shallow embayments or even, perhaps, a lagoon. This is indicated by their rare occurrence in the Brockenhurst Bed and the general finds in the shallow New Forest embayment of the Middle Eocene Sea. There are two types of early whales that occur in the Barton Clay Formation. The smaller whales belong to Zygorhiza and the larger to Basilosaurus. See: Halstead and Middleton (1972).

The known Eocene whale remains of Barton-on-Sea and the New Forest are now listed briefly, in sequence of the history of discovery.

Victorian times. Date unknown. The bones of a Basilosaurus were acquired or found by members of the Dent Family, of Barton Court. Bournemouth Natural Science Society possesses the bones and a general Barton fossil collection from the Dent family in 1912 (Chapman, 2009).
1872. By Dr. A. Wanklyn. In the Barton Clay of Barton-on-Sea - "Whole skull of a zeuglodont of moderate size." (Seeley, 1876) named it "Zeuglodon Wanklyni". Later it was assigned by Kellogg (1936) to Zygorhiza, the smaller of the two local Eocene whales.
1881. By Professor J.W. Judd. In the "Brockenhurst Beds" of the Headon Hill Formation. "A cetacean caudal (tail) vertebra". See: Seeley, 1881.
1907. By Mr. H. Eliot-Walton. In the Barton Clay of Barton-on-Sea - "A single cervical vertebra." Assigned by C.W. Andrews (1907) to Zeulodon wanklyni
1923. Mr. R. Egerton-Godwin found a dorsal vertebra and isolated vertebral epiphysis at Barton. Now in Natural History Museum.
1951. By Mr. N.C. Beaton and daughter. In the London Clay of the Isle of Sheppey - two fragments of a scapula. Named Anglocetus beatoni by Tarlo (1964).
1966. By Mr. K.B. Hobby. In the Barton Clay of Barton-on-Sea - Dorsal vertebra and caudal vertebra. Described by Halstead and Middleton (1972) as Basilosaurus sp..
1980 onwards. An occasional bone has fallen from the cliffs since about the 1980s from Middle Barton Clay to the east of Chewton Bunny.
2016. An ex-situ find of a primitive whale bone has been made at Studley Wood, within the New Forest, and near the Bracklesham-Barton boundary.

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SECTION 8 - PALAEOGEOGRAPHY AND PALAEOCLIMATOLOGY

8.1 PALAEOGEOGRAPHY - Introduction

The Barton Clay was deposited in a shallow embayment, connected indirectly to a precursor of the present English Channel. A particular complication is that a precursor of the Isle of Wight anticlinal structure was being developed at this time.

8.2 PALAEOGEOGRAPHY - [MECO SECTION TO BE ADDED HERE?]

The relationship of the Barton strata to the MECO, the Middle Eocene Climatic Optimum will now be discussed. The deposition of the Barton Clay was near this particular, very warm phase of the Eocene.

8.3 PALAEOGEOGRAPHY -

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SECTION 9. QUATERNARY - PLEISTOCENE - HOLOCENE

9.1 Pleistocene Strata - Subangular Flint Gravel and Brickearth etc. The main Pleistocene gravel terrace at Barton-on-Sea and eastern Highcliffe has a top surface near 90ft or 30m, in round figures. No detailed study has been made here, but this is at or near the 8th terrace of the River Avon as described in Bristow, Freshney and Penn (1991); see their figure 26 on p.87. Two or three metres of brown subangular, flint gravel is overlain by Brickearth (a brown silt), "for which a Late Devensian date has been given by thermoluminescence dating (Winkle 1981)" [comment in Barton (1984, p.17)]. There does not seem much doubt that the Pleistocene gravel and Brickearth of the Barton cliffs is from relatively late, i.e. near the end of, the Pleistocene [probably the last advance of the ice]. There seems no reason to doubt the previous conclusions.

See: Key Paper - Barton (1984) - Periglacial Features ..

A key paper, by Professor Max Barton on periglacial features in the cliffs between Highcliffe and Barton-on-Sea - front page only

Barton, M.E. 1984. Periglacial features exposed in the coastal cliffs at Naish Farm, near Highcliffe. Proceedings of the Hampshire Field Club and Archaeological Society, 40, 5-40. By Professor Max Barton. Civil Engineering Department, Southampton University.
Abstract: Superficial structures of periglacial origin have been examined in the cliff top scarp exposures at Naish Farm, near Highcliffe. They include a presumed valley bulge, frost wedge casts and involutions and cryoturbation structures. They are compared with similar fossil structures seen elsewhere in southern England and their affinities, origin and possible ages are discussed. It is suggested that in view of the frequently comparable, but usually less well-exposed, geological conditions in the Hampshire Tertiary Basin, such features may be of rather more common occurrence in the region than has been realised hitherto.

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A close-up view of typical Pleistocene, subangular, flint gravel, of the 90ft (30m) gravel terrace at Barton-on-Sea

Look, here, at an example the subangular, flint pebbles in the gravel terrace deposit at the top of the cliffs at Barton-on-Sea. It is similar to other Pleistocene, flint gravel deposits of southern England. It is periglacial in origin; the actual ice sheet at times reached as far south as the Mendip Hills (e.g. Cheddar Gorge) but down to this New Forest region, further south. The periglacial conditions were harsh, here, though and when the snow was melting in spring and early summer, the streams were much more vigorous than the quiet rivers of the region at present.

Typical Pleistocene, subangular, flint gravel of  Terrace 9, in the cliff, east of Barton Court, Barton-on-Sea, Hampshire, with a transitional junction to brickearth above, and, in contrast, with an abrupt iron-pan junction beneath

Observe in the photograph above a typical section through the Pleistocene deposits (Terrace 9) of Barton-on-Sea. The general, subangular flint pebble characteristics are well known and no significantly different from other Pleistocene gravels of the region. Here, there is a very smooth, upward transition into brickearth, a type of brown silt, probably of aeolian [eolian] origin. The soil at the top of the brickearth overhangs more because of the strengthening by plant roots. This is a common feature. Incidently rooks are common on these cliffs and the main "Rook Cliff" is not far to the east of here.

Evidence of a small ice-wedge in the Pleistocene gravel, of Terrace 9, at the cliff path down, just east of Barton Court, Barton-on-Sea with brickearth above

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A river channel in the Pleistocene gravel, Terrace 9, at Naish Farm, just east of Chewton Bunny, Highcliffe, Hampshire

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[STRIKING CRYOTURBATION OF PLEISTOCENE GRAVEL AT HOSKIN'S GAP, BARTON-ON-SEA]

Relatively complex origin of the Pleistocene gravel at Barton-on-Sea, with multiple podzol profiles within a block which has subsequently been tilted by periglacial freeze and thaw, - cryoturbation processes, east side, adjacent to Hoskins Gap, Barton-on-Sea, Hampshire

Cryoturbation of Pleistocene gravel at Barton-on-Sea, with the penecontemporaneously rotated block, east side, adjacent to Hoskins Gap, Barton-on-Sea, Hampshire

Shown above is a small part of the uppermost cliff, just to the east of Hoskin's Gap, near the centre of Barton-on-Sea cliffs. Here the Pleistocene gravel contains a tilted block of gravel with multiply podzol profiles, tilted in accordance with the bedding. The disturbance is a result of freeze and thaw cryoturbation. The most significant factor is that the podzol profiles here, and presumably elsewhere, are of Pleistocene, not post-Pleistocene (i.e. Holocene), origin.

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East of Barton Court, at the top of the cliffs there are good sections of Pleistocene, subangular, flint gravel lying unconformably on Eocene Barton Sand (Becton Sand Formation). At the location shown here, a few hundred metres east of Barton Court, a gravel terrace at about 30m height gives way eastward to a somewhat lower terrace. The periglacial river gravels contain much iron in ferric condition and this gives them their characteristic brown colour. Humic acids from decomposing vegetation in a podzol soil profile transports iron downwards in the relatively humid climate of southern England. The iron can be redeposited lower an iron-pan, and an example is shown here. These iron pans are not continuous for any great distance but in certain cases they are impervious enouth to hold up water. The Barton Sands beneath have been much oxidised and turned a more yellow colour than in the lower cliffs where eroded by the sea. Water goes through both the gravel and the underlying sand here and flows out at the base of the Barton Sands. This has been a major cause of landslipping in the past, and explains why landslides can sometimes be on a larger scale at Barton compared to Highcliffe.

Sedimentary structures in the gravels include shallow channels and some thin beds of sand. Cryoturbation structures from the freezing and thawing of the ground during periglacial conditions occur in places. Palaeolithic implements have been found here.

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9.2 Pleistocene Strata - Brickearth

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The brickearth above is a brown silt resembling loess. It has been claimed that in some places in southern England this is indeed of wind-blown origin. It may, however, in this area be largely river silt. Similar brickearth in the Hill Head area of Southampton Water has a clay mineral composition related to that of Chalk, but probably in that case there has been much solifluction from the Chalk of Portsdown Hill. The clay mineralogy of this brickearth in the Barton Cliffs has not been studied, but there is no nearby source of Chalk. Of course, the gravels beneath consist of the insoluble material, the flint, from the Chalk of the northern and western fringes of the Hampshire Basin, together with some Tertiary material. Exactly what was the origin of the brickearth is less obvious. Probably most has come ultimately from Tertiary clastic deposits with clay contributions from the Tertiary and Chalk and probably also with abraded flint debris (this is a suitable subject for a student project).

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Brickearth above Pleistocene fluvial gravel in a slipped block near the cliff top, east of Naish Farm, Barton-on-Sea, Hampshire

At the top of the cliff, over the gravel, is one to two metres of brickearth. This is a brown Pleistocene silt deposit, generally without visible stratification (there is one conspicuous parting in this area where the brickearth is very thick - 2 metres). It has been regarded by many as a loess deposit of wind-blown dust in cold conditions. Others have attributed it to solifluction. Near Salisbury a brickearth deposit has been found to contain the remains of lemmings which have been entombed in their burrows. It is of course possible that solifluction of a loess could occur.

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9.3 Cliff Vegetation

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The immature and patchy soils of the Barton Cliffs have, in a few places, American Yucca plants growing on the weathered clay, or argillaceous sand, with the locality here being the mid-cliff at the eastern end of the Barton-on-Sea cliff section

The Barton Cliff vegetation is beyond the scope of this webpage. Just a few details mAY be given if related to the geology. A few Yucca plants, which live naturally in North America, are present here and there on the cliffs. Since they could not have arrived here by any natural process, it is not obvious at to why they are present. Have they been purposely planted there or have they come from gardens which might have fallen over the cliffs? Because they tolerant of very varied pH conditions, they may be able to withstand the soil acidity of the Barton cliffs where pyrite (FeS2) from the strata is oxidising (to sulphates, like melanterite).

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CONTENTS - SECTION 10 - BEACH AND BEACH PROCESSES

10.1 BEACHES INTRODUCTION

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From Chewton Bunny stream outlet westward the coast has much rock armour protection. There are small beach embayments between artificial promontories of rock armout. Further west, from the Highcliffe Castle area westwards there are good sandy beaches. Much sand has come from Mudeford Spit, and ultimately from Hengistbury Head (and from the Bournemouth beaches which are supported by beach replenishment schemes).

Just to the east of Chewton Bunny (i.e. east of the large Highcliffe car park) there is a stretch of sandy beach in front of naturally eroding cliffs of Barton Clay. This stretch is largely preserved as a natural relic of the coast as it used to be. Further east near Barton, the coastline is spoilt by much rock armour. There are also mudslides or mudflows in that area. From Barton Court onwards towards the east there is an artificial coast with rock armour and no significant beaches now. At the end of this stretch, near Becton Bunny there is a natural coast again with cliffs and beaches. Erosion here has been much hastened by the effect of the Barton sea defences preventing longshore drift of beach material from the Barton and Highcliffe area. The overall coastal defence does not seem planned; there various, specific types of sea defences in front of specific parts of the coast. There are local areas of accumulation, much rock armour and major areas of loss of beach sediment. The sea defences have had a major effect on the Milford and Hurst Spit areas, greatly reducing the supply of sediment. As a result there has been major erosion at Milford-on-Sea and Hurst Spit is largely artificial now and is much threatened not just by erosion but by destruction. From time to time it is largely flattened and afterwards reloaded and rebuilt with debris from gravel pits. Surprisingly Hurst Castle has survived all this!

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CONTENTS - SECTION 11 - SPECIFIC LOCATIONS

11.1 LOCATION - Highcliffe to Mudeford - Friars Cliff etc.

[western part of region covered in this webpage]

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This section of coast between the main car park at Highcliffe and the end of the cliffs westward near Mudeford exposes the Upper Eocene, Lower Barton Beds underlain by the top of the Middle Eocene, Bracklesham strata. It is not as well exposed as previously. An interesting cliff of sand is visible in the western part but much of the eastern part of this stretch is now obscured by sea-defences and vegetation.

Comments on the previous state of the cliffs here were made by Wrigley (p. 173) in Burton (1931) and by the late fossil collector and violinist, Mr St. John Burton himself.
"Mr Wrigley remarked that the changes in the Run and in the egress of the rivers had been either the effect or the cause of alterations in the local direction of tidal force, so that active coast erosion had been transferred eastward to Milford and Hordle, leaving the cliff at Highcliff in a stable condition with accumulations of blown sand - to the chagrin of the present generation of fossil collectors who rarely were able to examine the riches of the Lower Barton Beds."
"The author [Burton] expressed his thanks to previous speakers. In the course of his own observations extending over a period of many years along this part of the Hampshire coast, he been impressed by the results of erosion eastward of Chewton Bunny at Highcliff and also below Barton Court. At the latter locality, the cliff had been cut back 25 yards [23m] in that number of years, which incidendently meant the loss of the most fossiliferous beds at this point. Temporarily increased activity of marine erosion here did not, however, necessarily correspond with the more important changes in the position of the Run. Under some conditions, the river-current flowed in a kind of fleet, extending for about a mile beyond Cliff End, and at half tide the surf broke on a submerged sandbank, formed between the 'fleet' and the open sea."

Dewatering structures in the Boscombe Sands of Friars Cliff, Highcliffe, Dorset

Dewatering ball and pillar structures in the Boscombe Sands, Friars Cliff, Highcliffe, Dorset, 2007

Dewatering ball and pillar structures in the Boscombe Sands, Friars Cliff, Highcliffe, Dorset as seen in 2005.

An interesting aspect of the sands as shown in the photographs is the presence of dewatering structures.

Ball and Pillow Structures at Friars Cliff

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[including the well-exposed Ball and Pillow structures etc. at Friars Cliff]

The Boscombe Sand Formation, Bracklesham Group, is seen in cliffs of Boscombe and particularly at Hengistbury Head. It is also exposed at Christchurch Bay at Friars Cliff. This is on the eastern side of Christchurch Harbour and is the location for the base of the Barton Clay. There it is characterised by Ball and Pillow Structures. These probably result from partial liquifaction of the water-saturated sediments, as a result of local earthquakes. The earthquake and liquifaction took place at a specific proven time. This was immediately prior to the deposition of the basal part of the Eocene Barton Clay. Unfortunately, the basal Barton Clay exposures, once very good (in Victorian times), are now degraded and overgrown. They were deteriorating when I when examined them in the early 1950s. Now they are almost concealed under bushes and trees. (Actually the basal Barton Clay is still well-exposed in the upper part of Friars Cliff, but this not accessible, at least not without special equipment.)

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A general view at low tide of Friars Cliff, between Mudeford and Highcliffe, for comparison with equivalent strata at Hengistbury Head, 22nd April, 2018

Friars Cliff, the sequence in the cliff in general perspective, as seen from the beach, 22nd April, 2018

Ball and Pillow Structure in the Boscombe Sand Formation at Friars Cliff, near Highcliffe, for comparison with equivalent strata at Hengistbury Head, April, 2018

More Ball and Pillow structure in the Boscombe Sand Formation at Friars Cliff, near Highcliffe, for comparison with equivalent strata at Hengistbury Head, April, 2018

Another Ball and Pillow structure in the Boscombe Sand Formation at Friars Cliff, near Highcliffe, for comparison with equivalent strata at Hengistbury Head, April, 2018

Yet another Ball and Pillow structure in the Boscombe Sand Formation at Friars Cliff, near Highcliffe, April, 2018

Sandstone with contortions due to penecontemporaneous liquifaction in the upper part of the Boscombe Sand Formation at Friars Cliff, near Highcliffe, April, 2018

The basal, Barton Clay, pebble bed, overlying the Boscombe Sand Formation, at Friars Cliff, near Highcliffe, April, 2018

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The Boscombe Sand Formation (the lowest bed at Hengistbury Head) has been subject to liquifaction by seismic shocks (not surprising because this was the time the "Alpine" tectonics started in the Dorset area). At Friars Cliff, on the other side of Christchurch Harbour and near Highcliffe, there are conspicuous dewatering structures, in addition to general earthquake disturbance. Examples are shown in images above (some adjusted with slight emphasis applied for clarity).

At Friars Cliff, to the west of the main Barton Clay section and between Highcliffe and Mudeford there used to be a good exposure of the base of the Barton Clay with the Boscombe Sands beneath [it has deteorated now]. The sands here have, in the past, been regarded as younger than the strata at Hengistbury Head and have received various names, including the Highcliffe Sands. They are now regarded as the equivalent of the Boscombe Sands at Hengistbury Head and have the same conspicuous pebble bed above and not far above that the prestwichianus Bed (with Nummulites prestwichianus). See Bristow, Freshney and Penn (1991), the Bournemouth Memoir, for further details.

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11.2 LOCATION - Highcliffe and Highcliffe Castle, West of Chewton Bunny

View eastward from Friars Cliff, Highcliffe towards the Holm Oak covered cliffs of Lower Barton Clay and on to the landslipping cliffs of Middle Barton Clay at Naish Farm and beyond to Barton-on-Sea

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[Highcliffe Castle subsection]

Exposures of the Lower Barton Clay are poor near Highcliffe Castle because of build-up of the beach and rampant growth of the Holm Oak or Evergreen Oak, Quercus ilex, over the cliffs

Highcliffe Castle on the cliff top above the Lower Barton Clay section and just to east of Friars Cliff, Dorset, Hampshire

Highcliffe Castle from the west side, this was formerly the home of Lord Stuart de Rothesay, inserted, photograph - afternoon, 12th November 2018

Highcliffe Castle looking northward, or landward, from the car park near the cliff-top, 12th November 2018

Going down the steps from Highcliffe Castle to the beach, 12th November 2018

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[end of Highcliffe Castle subsection]

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Lignite, probably from the Barton Clay of Hengistbury Head, and with borings containing sand with pyritic walls, washed up on the beach near  Highcliffe Castle

On the beach, a short distance east of the steps down to the beach at Highcliffe Castle, two pieces of lignite were found. These both contained Teredina [shipworm] borings. They are similar to shipworm borings found in lignic logs found in the Eocene strata of the Isle of Sheppey. Go to the Sheppey Fossils Website.

View eastward towards Barton-on-Sea and Hordle Cliff from the Highcliffe sea defences, in stormy weather, November 2018

Overgrown and largely artificial cliffs between the Highcliffe Castle steps and the main Highcliffe car park, Dorset

Looking towards Barton-on-Sea from the Highcliffe coast, to the east of  Highcliffe Castle, with a rough sea, on 12th November 2018

The cliffs near Highcliffe Castle were once subject to rapid erosion of the type that now takes place at the Naish Farm Section (in the Barton and Highcliffe Coast Erosion and Sea Defences webpage).

. Numerous small fossil and fish otoliths have been found in these cliffs in the beds A1 and A2 of the Lower Barton Clay. Now the beach has built up, just westward of the rock armour groynes of the Highcliffe sea defences. The sea rarely has much access to the cliffs now and the exposures are very poor. However, if you walk a few hundred metres further west to Friars Cliff then there is a good section of the Boscombe Sands overlain by the Lower Barton Clay. This is shown in the photographs which follow.

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11.4 LOCATION - Highcliffe Borehole at Highcliffe Castle

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Location map for the Highcliffe or Christchurch Borehole though Eocene strata

This borehole may be useful in providing information on the correlation of the strata across the mouth of Christchurch Harbour. The detailed log is not given here, only some summary data just as an example.

The log is valuable in proving the continuation of the section at Friars Cliff and showing the sequence downward. It seems to confirms that the strata in the upper part of the cliff at Hengistbury Head, really is of Lower Barton Clay (as demonstrated by fossil content). In other words there is NOt a thick sequence of (Bracklesham) ironstone-bearing clay beneath the Barton Clay. There is only 7.7m. of Barton Clay under the site. However, it must be noted that coring starts at 16.20 metres down and is not complete and regular until a depth of more than 30.23m.

Redrawn and simplified logs of the Highcliffe and Knapp Mill Boreholes, through the Eocene strata beneath the Barton Clay Formation

In 1984, the British Geological Survey had a borehole drilled through the Eocene strata at Highcliffe, very close to Highcliffe Castle. The details are in Freshney et al. 1984, "Geological Reports for DOE: Land Use Planning (a 113 page document with additional maps, a copy of which is Southampton University, NOC library)

The report does not show details of the Lower Barton Clay Formation because that was very close to the surface, but it did provide important sequence information down from the Boscombe Sand down to the Reading Beds. In other words, it provides a reference vertical section for understanding the Bournemouth cliffs. Only a very simplified version of the borehole log is shown in the above diagram. The detailed bed descriptions in the report are not shown here. The relevant descriptive data for the Highcliffe Borehole is in pages 103 to 108 of the report. See (Freshney, 1984) for full details.

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11.4b LOCATION - Chewton Bunny

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Waterfall beneath the bridge, up Chewton Bunny, Highcliffe, Dorset, after dark, January 2010

Chewton Bunny [i.e. "Chewton bourne - y"] is a small stream, with associated narrow valley, that has cut down into the Barton Clay. The distal part accords with sea level because it naturally adjusts down to the level near the mouth even though the coast retreats. It is effectively a "chine" like the Bournemouth chines (with bournes) and the Becton Bunny chine further east. The stream at Highcliffe is below the level of the Pleistocene gravel the valley is mainly cut into Barton Clay. It does not have a natural mouth now and discharges through a pipe wit associated rock armour. Chewton Bunny marks the boundary between Hampshire to the east and Dorset to the west [in modern terms; the historic boundary was much further west].

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11.2a LOCATION - Naish Farm Cliffs, East of Chewton Bunny

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Barton Clay, Highcliffe, 07.03.01

This photograph shows the base of the cliffs with fossiliferous Barton Clay, east of Highcliffe and below Naish Farm at about map reference SZ224931. The view is westward across the mouth of Chewton Bunny to a grassy hill at Highcliffe in the mist. On the top of the cliff here is a large car park which is reached by driving south at a sign "to the sea" from the centre of the main shopping street of Highcliffe. There are toilets at the car park.

A large groyne with blocks of Portland Stone (from the Isle of Purbeck) projects from the coast at Chewton Bunny. Longshore drift is from west to east because of the prevailing south-westerly winds. On much of the south coast of England groynes are able to bank up sand on the west side and cut off the supply of beach material to the east. This common phenomenon is known as "terminal scour" and where it happens local enhanced erosion and even the formation of embayments may take place. Here there is a retreating clay cliff and a sandy beach. Although much of the Barton and Highcliffe coast has lost its natural appearance and been turned into a defended embankment, this stretch remains relatively natural and is conserved as such largely for geological purposes. At one time the whole coastline here was like this and justifiably famous for fossil collecting. Good fossils can still be found in the clay and are occasionally washed out on the shore.

The lower cliff is eroded by the sea at high tide and particularly during storms. Part of it, like the projecting bulge here, consists of landslipped debris and part is of clay in situ. The best fossils tend to be found in the clay in place, although shells and occasionally vertebrate remains can also be found in the moved clay debris.

Barton Clay, Highcliffe, 07.03.01

Here is a representative part of the cliff in the Naish Farm stretch (on 07.03.01). Most of the cliff consists of the dark grey Barton Clay, but at the top are a few metres of Plateau Gravel of Pleistocene age. This is the remains of a periglacial river terrace, that we will consider further later. The light brown gravel is to some extent slumping over the clay. You can see two terraces of Barton Clay with liquid mud flowing over the brink from the upper one. The mud is supplied with water that runs out from the porous and permeable gravel at the top. The combination of steepening of the cliff by the sea and the supply of water from above results in many small landslides. Incidently, the clay is "steaming" because the morning sun is just beginning to warm the wet, dark, heat-absorbing surface.

Coastal retreat of the Barton Clay cliffs has averaged about a metre per annum, but may be locally higher in the Naish Farm area, because of the effects of sea defences to the west. The low cliff formed by erosion of the lowest terrace is, just here, mostly of landslipped debris and is not good for fossil collecting. On the beach there are numerous septarian nodules washed out of the clay, as shown above. The sea floor offshore consists of numerous, residual septarian nodules of this type.

A little further east there is an undisturbed cliff and by comparision with the cliff diagram provided in this website the position can be fixed. Bed C is easily recognised because it between two septarian bands and with a thin, burrowed, light-grey marl in its central part.

Gun emplacement and Barton Clay, Highcliffe, 07.03.01

The view is to the east, towards Barton on Sea, although it was not clearly visible because of mist when the photograph was taken. A terrace that was higher has descended to the beach now. Much of the clay here is in place, but there is some slumping, and some small channels of water and mud that descend to the beach. Notice the septarian nodules two-thirds way up the cliff in the left part of the photograph. These mark the top of bed C. This is a good place for collecting fossils, mostly because the clay is in situ . The tilted gun emplacement largely now buried under the beach sand. I knew this years ago when it was against the cliff, and still just about possible to get into. The gun emplacement was a cliff-top defence against invasion by Germany constructed in about 1940 in the Second World War. Accurate determination of the distance of this from the present cliff top would gove a measure of the extent of coastal retreat just here. See one at Abbotsbury on the Chesil Beach, and notice how the erosion there has been much less. The beach was photographed at low tide and consists largely of sand but much gravel. The sand has probably mostly come partly from sand within the Pleistocene gravel but also from much sand dispersed within the Barton Clay. Dark green glauconite grains in the beach sand demonstrate the Tertiary origin of much of it. The gravel is brown and subangular and has come from the Plateau Gravel. Only the clay is not accounted for. This is washed out to sea and in stormy conditions the muddy nature of the seawater is clearly seen.

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11.5 LOCATION - Barton-on-Sea - West of Barton Court (Middle Barton Clay)

West of the Barton Court area there is a long stretch of cliff with a grass recreational area, mainly without buildings directly above. The Cliff House Hotel is the only building and it is situated, at least at present, some way back from the cliff edge. Although the Barton Clay cliffs continue to collapse from time to time and place to place in their normal way there seems to be no specific problem at present (November 2018). On old maps the original (1823) Coast Guard Cottages were once situated near the cliff edge and they are shown on old maps (including the British Geological Survey, Lymington Sheet 330, 1893 edition, reprinted 1963). The cottages were together in a small terrace, extending towards the southwest and within an incomplete rectangular garden area. Go to Milton Heritage Website for a photograph of the six cottages. They were of the usual type, such as can still be seen at Lepe Beach, for example.

This western stretch of the Barton Cliffs is still in relatively natural condition, unlike the cliffs at Barton Court and to the east. The Middle Barton Clay is well exposed, but there are many mudslides. It does not seem very different from when I was fossil collecting there in the early 1950s. Up from the beach it is treacherous to walk on and there is high risk of sinking into a mudslide. I had expertise in bog walking and jumping on these cliffs and I never personally got stuck, although people with me did (and that includes a nun in her rather dirty habit). The extraction time for anyone stuck is usually at least two hours and the fire brigade may have to be called (it is very difficult to get people out because the soft clay of the mudslides has large, hard blocks within it). I have only met one person on these cliffs who has been bitten by an adder and I have never had problems with them. Fossil shells are very numerous on these cliffs and shark's teeth can be found.

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11.6 LOCATION - Barton-on-Sea - Cliff House - Hoskins Gap Area

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11.7 LOCATION - Barton-on-Sea - Barton Court area

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11.8 LOCATION - Barton-on-Sea - Barton Court East to Becton Bunny

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11.9 LOCATION - Becton Bunny Becton Sand - Oxidation of Pyrite

Jarosite - the Yellow Sulphate

Jarosite on the surface of fallen debris, Becton Sand, near Becton Bunny, east of Barton-on-Sea, Hampshire, 4th October 2013

Jarosite is a conspicuous yellow mineral, occurring as encrustations in places where oxidation of pyrite has taken place. It is an hydrated iron sulphate with potassium, sodium or ammonium. It is not true alum because it does not contain aluminium in any significant quantity. However, where it is present there is abundant pyrite and the theoretical potential for manufacturing alum. Associated with it may be the green ferrous sulphate - melanterite, known as copperas, but that is less common. These Becton Sand cliffs may show melanterite in addition to the conpicuous jarosite. Brownsea Island is the most notable historic site for copperas production, but Alum Chine, Bournemouth is another well-known location. Alum Bay, Isle of Wight also takes its name from pyrite and copperas production. STRATIGRAPHY continued:

Becton Sand Formation or Barton Sands

Barton Sand, east of Barton

The Barton Sands or Becton Sand comprises about 27 to 30m of light-coloured, fine-grained sands, with some loamy and clayey beds, particularly at the base and near the top. These sands can be seen clearly in the photographs taken at the eastern end of the Barton sea defences. Because beach sediment can no longer easily reach here from the west (longshore drift is from west to east), being arrested by the sea-defences, erosion is intense. This is a site of "Last Groyne Syndrome", with cliffs to some extent purposely sacrificed by holding back shingle to protect the cliff-top properties of Barton-on-Sea. The increased erosion here yields excellent exposures of the Barton Sand or Becton Sand. The junction with the Barton Clay, marked by the Turritella-rich and iron-rich Shell Bed or Stone Band, is not exposed at present here, however, and it is the upper part of the Chama Bed which is first seen, unprotected, on the shore.

The section continues eastward to the small oblique valley of Becton Bunny. The Headon Hill Formation of clays with some minor siderite and limestone and many "freshwater" fossils follows and is well exposed at Beacon Cliff, Taddiford (Long Mead End) and beyond in Hordle Cliff and towards Hurst Spit.

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STRATIGRAPHY continued:

Becton Sand Formation - Bed I

A view from the cliff edge of the last groyne syndrome at the eastern end of the Barton-on-Sea sea defences, with Becton Bunny and Hordle Cliff beyond, Hampshire, 4th March 2013

Bed I, a soft sandstone bed of the Becton Sand Formation, east of Barton-on-Sea and near Becton Bunny, Hampshire, 4th March 2013

Next follows 7.9m (26 feet) of grey, yellow and white sand. It consists of greyish, micaceous sands in which the grains are held together by fine argillaceous natter. Below Barton Court parts of it are vivid yellow in colour, but it seems paler at a low level near the beach. It has been described as unfossiliferous, but moulds of shells occur in the upper part (Burton,1929;1933). A photograph above shows the unit after the unusually heavy rain of the winter 2012 to 2013. Grey clay derived from water above the Becton Bunny Bed (J) has run down the cliff. The Becton Bunny Bed itself is not conspicuous because of fallen sand from the Long Mead End Bed (K).

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STRATIGRAPHY continued

Becton Bunny Bed or the Olivella branderi Bed - Bed J

[The bed with the dwarf Olive Shells]

Becton Sands etc west of Becton Bunny, Sept 2002, cliff-top view

Fallen blocks of clay with shells from the Becton Bunny Bed, Becton Sand Formation, near Becton Bunny, east of Barton-on-Sea, Hampshire, 4th October 2013

Becton Sands with Becton Bunny Bed, west of Becton Bunny, Barton

There is good access to the Becton Sands, with fallen material from the Becton Bunny Bed. It descends to the beach a short distance further east.

The Becton Bunny Bed above the white sand of Bed I, at the mouth of Becton Bunny, east of Barton-on-Sea, Hampshire, March 2013

This is at the mouth of Becton Bunny. It probably was once called Beacon Bunny (or Bourne) and took its name from the adjacent Beacon Cliff, to the east, where there was a fire-beacon. The valley is narrow and oblique to the coast, so that with coast erosion the mouth would appear to moved westward. The Becton Bunny Bed is accessible here and clear of debris but, however, near the valley it may be weathered and not necessarily contain well-preserved shells. It may be worth checking the cliffs on the far side (eastern) of the valley. Fossils are common in the clay and if not found in situ they will easily be found in fallen blocks.

The gastropod, Olivella branderi, in Bed J, the Becton Bunny Bed, east of Barton-on-Sea, Hampshire, 2013

This grey argillaceous unit is well-seen in the photographs. It is 7.9m (26 feet) thick. Drab grey sandy clay forms the lowest 1.8m (6 feet), followed by 6m (20 feet) of greenish grey sandy clay, with much ferruginous matter near the surface. This causes it to weather to a pinkish drab colour. At about 3m (10 feet) from the base there are small spheroidal ferruginous concretions, averaging only about 10 cm (4 inches) in diameter (Burton,1929; 1933). Marine to brackish fossils are numerous but fragile and difficult to collect. The distinctive gastropod Olivella branderi is abundant, but also occurs in the bed above. Olivella branderi (J. Sowerby) has a superficially close resemblance to the Purple Dwarf Olive, Olivella biplicata Sowerby of the western coast of North America. It about the same size, and, as you can see in the photograph, there are traces preserved of similar colour marking. Olive shells occur in various parts of the world today but are mostly Indo-Pacific, tropical forms. Most of them are larger than this "olive" (although the Twisted Plait Olive, Olivancillaria contortuplicata Reeve of the Carribean to Patagonia is also a small form. For more information on olive shells see Dance (1992).

A related species of Olivella is found living today in sandy shallow subtidal and low intertidal sediments of the eastern Pacific coast of the USA. It usually lives partially buried and feeds on detrital material. Often, large numbers of shells are washed onto sandy beaches of the west coast of the Pacific northwestern United States. The olive shells in the Becton Bunny Bed seem to be more or less in place and not accumulated as shell banks, (see reference: Marine Biology - soft shore.).

Nautilus has been found but Turritella does not occur so high in the Barton sequence.

A brief summary of the main fauna is as follows:
Olivella branderi (Marine gastropod) - very abundant.
Nucula (marine bivalve)
Pitar (marine bivalve, a Venus clam, Veneridae)
Potamides (estuarine turreted gastopod)
Corbicula (estuarine bivalve)
Bayania (estuarine gastropod)
Nautilus (marine cephalopod)
Callianassa, a mud-shrimp, occurs in soft concretions.

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CONTENTS - SECTION 12. LANDSLIDES AND CLIFF FALLS

12.1 LANDSLIDES - Introduction: Go to other webpage
Please click -- Barton - Coastal Erosion and Landslides.

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UNPLACED

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FINAL PART

13.1 ACKNOWLEDGEMENTS

I am very grateful to the late Paul Clasby for some very useful comments and corrections. Caroline Clasby and other students have assisted me in the field. I thank Dr Ken Collins and Sarah Snowden for discussing septarian nodules in the field and the offshore distribution of Barton Clay horizons. I am much obliged to Alan Morton for further information regarding Basilosaurus.

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13.2 BIBLIOGRAPHY AND REFERENCES

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APPENDIX - CLAY MINERALOGY OF BARTONIAN STRATA [in place]

Appendix - Clay Mineralogy

Introduction

Clay mineral distributions in the Hampshire Basin, based on the work of Gilkes (1968), with some further palaeoenvironmental interpretation

Diagram summarising the clay mineralogy of the Barton Clay, Barton Sand and Headon Hill Formation from Highcliffe to Milford-on-Sea, Hampshire, redrawn with modifications after Professor Bale (1984)

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Summary of Clay Mineral Abundances

The following notes are based on the excellent, detailed work of "Tunde" Bale (1984) which summarises the clay mineralogy of the Barton Formation. Much more detail is given and the interested reader should consult the original thesis (available for reference in the National Oceanography Library, the National Oceanography Centre, Southampton).

The clay mineralogy of the Upper Eocene succession of the Hampshire Basin essentially comprises illite which is greater or equal to smectite. In turn smectite is greater or equal to kaolinite (the coarser and non-expandible clay mineral). This is more abundant than the mixed-layer, illite-smectite. Chlorite is common but in quantitative terms is minor compared with the other clay minerals. This assemblage is similar to that observed by Gilkes (1966), who did the pioneering work on the Hampshire Basin clay mineralogy. A major advance of the Bale work is the recognition of the mixed-layered phases, which he identified and estimated semi-quantitatively.

Dioctahedral smectite and illite dominate. Together, these two phases generally account for about 70 percent of the clay fractions. Illite occurs in higher amounts than smectite in the non-marine 'Lower Headon Beds', whilst approximately equal amounts of illite and smectite occur in the marine Barton Clay and Barton Sand Formations. Some horizons however. possess considerable higher smectite contents. These notably include the marine sequence at Whitecliff Bay and the lower parts of the Barton Sand at Barton. Kaolinite and illite-smectite occur in lesser amounts of around 8-20%. Chlorite occurs only as a minor constituent in a limited number of the marine sediments, and the lignitic clays. In addition, some smectites with chlorite interlayers occur in some of the lignitic clays and limestones, with abundant carbonaceous matter. Deviations from the above occur in the succession at Alum Bay. At this locality the smectite, illite-smectite and chlorite are absent or occur in very low amounts in the clay fractions of the pebble bed and the Barton Sand. The depletions are of high significance in the palaeosol at the top of the Barton Sand and the succeeding lower parts of the Headon Hill Formation at Hatherwood Point, near Alum Bay, Isle of Wight. The depletion of these phases is accompanied by a substantial increase in the amounts of kaolinite and/or illite. This peculiar clay mineralogy at Alum Bay is thought to be due to localised differential derivation of detritus and/or the imprint of surficial (acid soil pedogenesis) processes. These are discussed elsewhere

Discussion of the Clay Mineralogy

The discussion of the clay mineralogy of the Upper Eocene sediments is centred on three factors that generally dictate the assemblage and relative abundance of clay minerals in sedimentary rocks. These are the nature of the source; contemporaneous neoformations and/or alterations; and sedimentological factors such as 'differential settling'. Diagenetic transformations are not considered important because of the shallow burial (~ 200m depth) history of the Upper Eocene succession under study. The clay assemblage of the sediments and those of other Palaeogene sediments in southern England were then employed for deducing the palaeo-environmental conditions and presenting a new view of the derivation of the clay assemblage.

Derivation of the Clay Assemblage

i) Constancy of Source

The general constancy of the illite-smectite-kaolinite-illite/ smectite assemblage in the Upper Eocene sediments suggests constancy of sources of detritus. A similar deduction of constancy of source was made by Blondeau and Pomerol (1968) from a study of heavy mineral assemblages in the sediments. With illite and smectite dominating in the clay fractions, the clays belong to the 'eastern province' assemblage of Gilkes (1966, 1967). This, Gilkes believed, was derived mainly from rocks exposed to the north and east of the Hampshire Basin. This hypothesis is broadly acceptable. However, recent advances in the geology of southern England necessitate re-assessing and updating views on the clay derivation.

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For more on coast erosion and sea defences at Barton and Highcliffe see:

Barton and Highcliffe Coast Erosion Webpage.

Go west to:

Hengistbury Head and Mudeford Spit?

Go east to:

Hordle Cliff and Milford-on-Sea?

or

Hurst Spit?

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13.2 BIBLIOGRAPHY AND REFERENCES

Please go to Highcliffe, Barton and Hordle Cliff - Bibliography and References .

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|Home and List of Webpages |Field Guides Intro. |Hordle Cliff and Milford-on-Sea |Barton and Highcliffe - Coast Erosion |Highcliffe, Barton and Hordle - Bibliography |New Forest Geology |Solent Estuaries - Introduction




This is the general geology webpage on the Barton-on-Sea cliffs, not the coast erosion webpage.


MORE BARTON AND HIGHCLIFFE!
See also associated webpages
Barton-on-Sea and Highcliffe - Geological Field Guide

Coast Erosion and Sea Defences at Barton-on-Sea and Highcliffe

Barton and Highcliffe - Erosion History

Highcliffe, Barton and Hordle - Bibliography

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Copyright © 2018. Ian West, Tonya West and Joanna Bentley. All rights reserved. This is a purely academic website and images and text may not be copied for publication or for use on other webpages or for any commercial activity. A reasonable number of images and some text may be used for non-commercial academic purposes, including field trip handouts, lectures, student projects, dissertations etc, providing source is acknowledged. I thank the many people who have accompanies me or assisted me on various field trips. I thank Alan Morton for helpful guidance on the topic of fossil whales.

Disclaimer: Geological fieldwork involves some level of risk, which can be reduced by knowledge, experience and appropriate safety precautions. Persons undertaking field work should assess the risk, as far as possible, in accordance with weather, conditions on the day and the type of persons involved. In providing field guides on the Internet no person is advised here to undertake geological field work in any way that might involve them in unreasonable risk from cliffs, ledges, rocks, sea or other causes. Not all places need be visited and the descriptions and photographs here can be used as an alternative to visiting. Individuals and leaders should take appropriate safety precautions, and in bad conditions be prepared to cancell part or all of the field trip if necessary. Permission should be sought for entry into private land and no damage should take place. Attention should be paid to weather warnings, local warnings and danger signs. No liability for death, injury, damage to, or loss of property in connection with a field trip is accepted by providing these websites of geological information. Discussion of geological and geomorphological features, coast erosion, coastal retreat, storm surges etc are given here for academic and educational purposes only. They are not intended for assessment of risk to property or to life. No liability is accepted if this website is used beyond its academic purposes in attempting to determine measures of risk to life or property.

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Dr Ian West, author of these webpages

Ball and Pillow Structure, as shown in an old monochrome photograph of Ian West behind the barbed wire, on Friars Cliff in the 196os or 70s

Webpage - written and produced by:


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

[Ian has been working on these cliffs since about 1950 or before, and after just a few field trips during the Second World War.]

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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.


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