The Teign Valley Group is a late
Devonian
The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...
to late/middle
Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning 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 ...
) in north
Cornwall
Cornwall (; or ) is a Ceremonial counties of England, ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, ...
through
Devon
Devon ( ; historically also known as Devonshire , ) is a ceremonial county in South West England. It is bordered by the Bristol Channel to the north, Somerset and Dorset to the east, the English Channel to the south, and Cornwall to the west ...
and into west
Somerset
Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...
in southwest
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 name is derived from the valley of the
River Teign
The River Teign is a river in the county of Devon, England. It is long and rises on Dartmoor, becomes an estuary just below Newton Abbot and reaches the English Channel at Teignmouth.
Toponymy
The river-name ''Teign'' is first attested in a ...
. The Group comprises (in ascending order i.e. oldest first) the Barras Nose, Trambley Cove, Teign Chert and Dowhills Mudstone formations. It also includes the Brendon and St Mellion formations whose stratigraphical context is unclear since all known boundaries of these two unit are tectonic. The Brendon Formation slates extend from
Tavistock
Tavistock ( ) is an ancient stannary and market town and civil parish in the West Devon district, in the county of Devon, England. It is situated on the River Tavy, from which its name derives. At the 2011 census, the three electoral wards (N ...
west to
Bodmin Moor
Bodmin Moor () is a granite moorland in north-eastern Cornwall, England, United Kingdom. It is in size, and dates from the Carboniferous period of geology, geological history. It includes Brown Willy, the highest point in Cornwall, and Rough To ...
. The St Mellion Formation sandstones, siltstones and mudstones are found from
Holne northeastwards. The Teign Valley Group was formerly known as the Lower Culm Group or Lower Culm Measures.
[http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=TEVY (BGS on-line lexicon of rock units)]
References
{{Reflist
Carboniferous System of Europe
Devonian System of Europe
Geology of England
Geological groups of the United Kingdom
Mudstone groups
Chert groups
Sandstone groups
Limestone groups
Basalt groups
Tuff groups