The Bracklesham Group (formerly Bracklesham Beds), in

geology Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...

, is a series of

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

s and

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

s, with sandy and lignitic beds, in the middle

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

of 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 ...

and

London Basin The London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea. The basin formed as a result of compr ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. The type section of the Bracklesham Group is the sea cliffs at

Whitecliff Bay Whitecliff Bay is a sandy bay near Foreland which is the easternmost point of the Isle of Wight, England, about two miles south-west of Bembridge and just to the north of Culver Down. The bay has a shoreline of around and has a popular sand ...

on the

Isle of Wight The Isle of Wight (Help:IPA/English, /waɪt/ Help:Pronunciation respelling key, ''WYTE'') is an island off the south coast of England which, together with its surrounding uninhabited islets and Skerry, skerries, is also a ceremonial county. T ...

, and it is also well developed on the mainland. The Group gets its name from a section at Bracklesham in

Sussex Sussex (Help:IPA/English, /ˈsʌsɪks/; from the Old English ''Sūþseaxe''; lit. 'South Saxons'; 'Sussex') is an area within South East England that was historically a kingdom of Sussex, kingdom and, later, a Historic counties of England, ...

. The thickness of the deposit is around 120 m.

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 preserve ...

mollusca Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

are abundant, and

fossil fish Fish began evolving about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish line ...

are to be found, as well as ''

Palaeophis ''Palaeophis'' ('ancient snake') is an extinct genus of marine snake that is the type genus of the extinct snake family Palaeophiidae. Described species within this genus lived in the Eocene epoch, with some unnamed or questionable records from ...

'', a sea-snake, and ''

Puppigerus ''Puppigerus'' is an extinct genus of sea turtle from the Eocene. It is known from finds in the United States, the United Kingdom, Belgium, Denmark, and Uzbekistan. Taxonomy ''Puppigerus'' was described by Edward Drinker Cope in 1870. As of 1997 ...

'', a

sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerh ...

Nummulite A nummulite is a large lenticular fossil, characterised by its numerous coils, subdivided by septa into chambers. They are the shells of the fossil and present-day marine protozoan ''Nummulites'', a type of foraminiferan. Nummulites commonly vary ...

s and other

foraminifera Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...

also occur. The Bracklesham Group lies between the Barton Clay above and the Bournemouth Beds, Lower Bagshot, below. In the London Basin, these beds are represented only by thin sandy clays in the Middle Bagshot group. In the

Paris Basin The Paris Basin () is one of the major geological regions of France. It developed since the Triassic over remnant uplands of the Variscan orogeny (Hercynian orogeny). The sedimentary basin, no longer a single drainage basin, is a large sag in ...

the "Calcaire grossier" lies upon the same geological horizon.

References

;Attribution * This cites: **F. Dixon, ''Geology of Sussex'' (new ed., 1878) **F. E. Edwards and SV Wood, ''Monograph of Eocene Mollusca'', Palaeontographical Soc. vol. i. (1847–1877) **''Geology of the Isle of Wight'', ''Mem. Geol. Survey'' (2nd ed., 1889) **C. Reid, ''The Geology of the Country around Southampton'', Mem. Geol. Survey (1902).
New Forest Geology Guide
Geological groups of the United Kingdom Eocene Series of Europe Paleogene England Lithostratigraphy of England {{UK-geologic-formation-stub