The Teign Valley Group is a late Devonian to late/middle Carboniferous lithostratigraphic group (a sequence of rock strata) in north Cornwall through Devon and into west Somerset in southwest England. The name is derived from the valley of the River Teign. 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 west to Bodmin Moor.British Geological Survey 1993 Tavistock, England and Wales sheet 337 Solid & Drift geology 1:50,000 provisional series (Keyworth, Nottingham: BGS) The St Mellion Formation sandstones, siltstones and mudstones are found from Holne northeastwards.http://mapapps.bgs.ac.uk/geologyofbritain/home.html BGS map viewer 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)
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