Diplocynodon hantoniensis Nicholson and Lydekker

Barton Beds (now the Barton Group) is the name given to a series of grey and brown

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

s, with layers of

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

, of Upper

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

age (around 40 million years old), which are found in the

Hampshire Basin The Hampshire Basin is a geological basin of Palaeogene age in southern England, underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex. Like the London Basin to the northeast, it is filled with sands and clays of Paleocene and yo ...

of southern England. They are particularly well exposed in the

cliff In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on co ...

s at

Barton-on-Sea Barton on Sea (often hyphenated as Barton-on-Sea) is a cliff-top village in Hampshire, England with close connections, physical, governmental and commercial, to the inland town, New Milton which is its civil parish to the north. As a settlement, ...

, which is the type locality for the Barton Beds, and lends its name to the Bartonian age of the Eocene

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

. The clay is abundant in

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s, especially

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant taxon, extant species of molluscs are recognized. The number of fossil sp ...

. The beds are found in the

, and are well exposed in the cliffs of Barton,

Hordle Hordle is a village and civil parish in the county of Hampshire, England. It is situated between the Solent coast and the New Forest, and is bordered by the towns of Lymington and New Milton. Like many New Forest parishes Hordle has no vill ...

, and on the

Isle of Wight The Isle of Wight ( ) is a county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the largest and second-most populous island of England. Referred to as 'The Island' by residents, the Isle of ...

.Archibald Geikie, (1903), ''Text-book of Geology, Volume 2'', page 1233. The cliffs at Barton are the world type locality for the Barton Beds.Janet M. Hooke, (1998), ''Coastal Defence and Earth Science Conservation'', pages 246-7. Geological Society. The beds consist of grey, greenish and brown

s with bands of

and have long been well known for the abundance and excellent preservation of their fossils. More than 500 species have been recorded,Charles Panzetta Chatwin, (1960), ''British Regional Geology: the Hampshire Basin and adjoining areas'', page 68. Geological Survey of Great Britain of which, over half are

, including numerous turret shells and lamellibranchs.Derrick Knowlton, (1973), ''The Naturalist in Central Southern England: Hampshire, Berkshire, Wiltshire, Dorset and Somerset'', page 51. David & Charles Sharks teeth are common, and the beds have yielded remains of

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

es,

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

s, and

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s. Plant fossils are also abundant. In the 1840s fossils were found in the "crocodile bed" at Hordle cliff, which belonged to an extinct species of alligator, which was subsequently named ''

Diplocynodon ''Diplocynodon'' is an extinct genus of alligatoroid that lived during the Paleocene to Middle Miocene in Europe. It looked very similar to the modern caiman in that it was small and had bony armour scutes covering its neck, back, belly, and tail ...

hantoniensis'', after the county of

Hampshire Hampshire (, ; abbreviated to Hants) is a ceremonial county, ceremonial and non-metropolitan county, non-metropolitan counties of England, county in western South East England on the coast of the English Channel. Home to two major English citi ...

(''Hantonia'' being a Latinization based on the Anglo-Saxon name ''Hantescire''). Above the highly

fossiliferous A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

Barton Clay, there is a sandy series with few

s; these are the Headon Hill or Barton Sands. Today, the Barton Beds are rather poorly exposed in many sections due to coastal protection works.P. J. Brenchley, Peter Franklin Rawson, (2006), ''The geology of England and Wales'', page 423 The ''Barton Beds'' are of Upper

age, and the area was covered with an inland sea, and the temperature was higher than at the present day. The term "

Bartonian The Bartonian is, in the ICS's geologic time scale, a stage or age in the middle Eocene Epoch or Series. The Bartonian Age spans the time between . It is preceded by the Lutetian and is followed by the Priabonian Age. Stratigraphic definitio ...

" was introduced by

Karl Mayer-Eymar Karl David Wilhelm Mayer-Eymar (29 July 1826 – 25 February 1907) was a Franco-Swiss paleontologist and geologist known for his work on classifying the stratigraphy of the Tertiary into 12 stages. He was born Karl Mayer but added the anagram Eymar ...

in 1857 for the

continental Continental may refer to: Places * Continent, the major landmasses of Earth * Continental, Arizona, a small community in Pima County, Arizona, US * Continental, Ohio, a small town in Putnam County, US Arts and entertainment * ''Continental'' ( ...

equivalents of the series.

References

{{Reflist, refs= {{EB1911, inline=1, first=John Allen, last=Howe, wstitle=Barton Beds, volume=3, page=453 This cites: * "Geology of the Isle of Wight," ''Mem. Geol. Survey'' (2nd ed., 1889) * "The Geology of the Country around Southampton," ''Mem. Geol. Survey'' (1902).

External links

''Barton and Highcliffe, Eocene Strata''
''Geology of the Wessex Coast of southern England'', by Ian West Sediments Paleogene England Geologic formations of England Lithostratigraphy of England