The Britannia Catchments Group is a

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

lithostratigraphic Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology. In general, strata are primarily igneous ...

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic iden ...

(a sequence of

rock strata In geology and related fields, a stratum (: strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ...

or other definable geological units) present in all parts of

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

and including the

Isle of Man The Isle of Man ( , also ), or Mann ( ), is a self-governing British Crown Dependency in the Irish Sea, between Great Britain and Ireland. As head of state, Charles III holds the title Lord of Mann and is represented by a Lieutenant Govern ...

. It includes a wide range of deposits including

alluvium Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

river terrace Fluvial terraces are elongated terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplain, other fluvial t ...

deposits,

peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

, cover sand and

blown sand Blow commonly refers to: *Cocaine *Exhalation *Strike (attack) Blow, Blew, Blowing, or Blown may also refer to: People * Blew (surname) * Blow (surname) Arts and entertainment Music * The Blow, an American electro-pop band Albums * ''Blow ...

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

lacustrine A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...

mass movement Mass movement may refer to: * Mass movement (geology), the movement of rock and soil down slopes due to gravity * Mass movement (politics), a large-scale social movement * Mass movement (biology), a type of movement in the digestive system { ...

periglacial Periglaciation (adjective: "periglacial", referring to places at the edges of glacial areas) describes geomorphic processes that result from seasonal thawing and freezing, very often in areas of permafrost. The meltwater may refreeze in ice wedg ...

and aeolian origin. Its lower boundary is defined as an unconformable contact with the underlying Albion Glacigenic Group (in England and Wales), the

Caledonia Glacigenic Group The Caledonia Glacigenic Group is a Quaternary lithostratigraphic group (a sequence of rock strata or other definable geological units) present across the whole of Great Britain to the north and west of the furthest limit of Devensian glaciation ...

(in Scotland), the Dunwich Group,

Crag Group The Crag Group is a geological group outcropping in East Anglia, England and adjacent areas of the North Sea. Its age ranges from approximately 4.4 to 0.478 million years BP, spanning the late Pliocene and early to middle Pleistocene epochs. It ...

or with older

bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bed ...

. Its upper boundary is generally the present day ground surface but it interfingers locally with the British Coastal Deposits Group. The group is subdivided into more geographically restricted subgroups by river catchments of which the following are defined:MCMILLAN, A A, HAMBLIN, R J O, and MERRITT, J W. 2005. ''An overview of the lithostratigraphical framework for the Quaternary and Neogene deposits of Great Britain (Onshore).'' British Geological Survey Research Report RR/04/04 38pp. p. 11-14 * Northern Highlands and Argyll Catchments Subgroup * Grampian Catchments Subgroup * Tay Catchments Subgroup * Forth Catchments Subgroup * Clyde Catchments Subgroup * Tweed Catchments Subgroup * Solway Catchments Subgroup * Northumbria Catchments Subgroup * Isle of Man Catchments Subgroup * Cheshire-North Wales Catchments Subgroup * Yorkshire Catchments Subgroup * Trent Catchments Subgroup * Severn and Avon Catchments Subgroup * West Wales Catchments Subgroup * Ouse-Nene Catchments Subgroup * Yare Catchments Subgroup * Somerset Catchments Subgroup * Thames Catchments Subgroup * Suffolk Catchments Subgroup * Cornubian Catchments Subgroup * Solent Catchments Subgroup * Sussex Catchments Subgroup * South Kent Catchments Subgroup Subgroups may also be defined for the various Scottish island groups.

References

{{Reflist Quaternary geologic formations Geology of England Geology of Scotland Geology of Wales Geological groups of the United Kingdom