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

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".

SECTION 2 - INTRODUCTION - MAPS

2.1. INTRODUCTION - Topographic Maps and Locations

Maps and Location Views

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

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2.2. INTRODUCTION - Geological Maps

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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.

SECTION 3 - EOCENE STRATIGRAPHY - INTRODUCTORY

3.1 STRATIGRAPHY - Introductory Eocene - General

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.

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.

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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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

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:]

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

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

STRATA:

4.0 Lower Barton Clay - Description

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

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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).

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 ready for addition]

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

STRATA: 5. Middle Barton Beds - Barton Clay.

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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.

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."

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.]

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, 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

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.

7.1 EOCENE - MECO - the 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. Incidentally, crocodiles (the Hampshire Crocodile - Diplocynodon hantoniensis) occur in the Barton Clay and more commonly in the Headon Hill Formation, a short distance above; their occurrence was probably related to the warm climatic conditions in the Eocene, not unlike those of Florida, at the present time.

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8. Pleistocene Strata  

8.1 Pleistocene Gravel (Plateau Gravel)

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.

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

HYDROZOA (List of St. John Burton, 1933)

Axopora michelini Duncan
Holaraea parisiensis (Michelin)

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.

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.

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

BRACHIOPODA (List of St. John Burton, 1933)

Terebratula sp. nov

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

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.

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)
[bottom of page 154]
"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)

SCAPHOPODA(List of St. John Burton, 1933)

Dentalium (Laevidentalium) acicular Deshayes
Dentalium striatum Sowerby

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]

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)

.

(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

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.]

7.2 FOSSILS - Introduction

7.3 FOSSILS - Introduction

7.4 FOSSILS - Introduction

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.

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.

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 -

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 ..

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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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.

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.

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

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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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.

9.3 Cliff Vegetation

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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).

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!

CONTENTS - SECTION 11 - SPECIFIC LOCATIONS

11.1 LOCATION - Highcliffe to Mudeford - Friars Cliff etc.

[western part of the coast covered in this webpage]

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.

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