Barton Beds
Encyclopedia
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
s, with layers of sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
, of Upper Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
age (around 40 million years old), which are found in the Hampshire Basin
Hampshire Basin
The Hampshire Basin is a geological basin of Paleogene age in southern England, underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex...
of southern England. They are particularly well exposed in the cliff
Cliff
In geography and geology, a cliff is a significant vertical, or near vertical, rock exposure. Cliffs are formed as erosion landforms due to the processes of erosion and weathering that produce them. Cliffs are common on coasts, in mountainous areas, escarpments and along rivers. Cliffs are usually...
s at Barton-on-Sea, which is the world type locality for the Barton Beds, and lends its name to the Bartonian age
Bartonian
The Bartonian is, in the ICS's geological timescale, a stage or age in the middle Eocene epoch or series. The Bartonian age spans the time between and . It is preceded by the Lutetian and is followed by the Priabonian age.-Stratigraphic definition:...
of the Eocene epoch
Epoch (geology)
An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...
. The clay is abundant in fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s, especially molluscs.
The beds are found in the Hampshire Tertiary basin
Hampshire Basin
The Hampshire Basin is a geological basin of Paleogene age in southern England, underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex...
, and are well exposed in the cliffs of Barton
Barton on Sea
Barton on Sea is a coastal village situated in Hampshire, England. As a settlement, Barton has a history dating back to Anglo-Saxon times, although the modern village was largely built in the 20th century. It is effectively a suburb of New Milton...
, Hordle
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 village centre...
, and on the Isle of Wight
Isle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
. The cliffs at Barton are the world type locality for the Barton Beds. The beds consist of grey, greenish and brown clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
s with bands of sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
and have long been well known for the abundance and excellent preservation of their fossils. More than 500 species have been recorded, of which, over half are molluscs, including numerous turret shells and lamelli-branchs. Sharks teeth are common, and the beds have yielded remains of coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
s, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...
es, mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s, reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s, and bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
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
Diplocynodon is an extinct genus of alligatoroid that lived during the Paleocene to middle Miocene 49 million years ago 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
Hampshire is a county on the southern coast of England in the United Kingdom. The county town of Hampshire is Winchester, a historic cathedral city that was once the capital of England. Hampshire is notable for housing the original birthplaces of the Royal Navy, British Army, and Royal Air Force...
(Hantonia being a Latinization based on the Anglo-Saxon name Hantescire). Above the highly fossiliferous Barton Clay, there is a sandy series with few fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
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.
The Barton Beds are of Upper Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
age, and the area was covered with an inland sea, and the temperature was higher than at the present day. The term "Bartonian
Bartonian
The Bartonian is, in the ICS's geological timescale, a stage or age in the middle Eocene epoch or series. The Bartonian age spans the time between and . It is preceded by the Lutetian and is followed by the Priabonian age.-Stratigraphic definition:...
" was introduced by Karl Mayer-Eymar in 1857 for the continental
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
equivalents of the series.
External links
- Barton and Highcliffe, Eocene Strata, Geology of the Wessex Coast of southern England, by Ian West