Teign Valley Group

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.[1][2] The St Mellion Formation sandstones, siltstones and mudstones are found from Holne northeastwards.[3] The Teign Valley Group was formerly known as the Lower Culm Group or Lower Culm Measures.[4]

Teign Valley Group
Stratigraphic range: Famennian (Devonian) to Marsdenian (Carboniferous)
Folded slate at Penally Point near Boscastle in Cornwall, England
Type	Group
Unit of	Culm Supergroup
Sub-units	Barras Nose Formation, Trambley Cove Formation, Teign Chert Formation, Dowhills Mudstone Formation, Boscastle Formation, Brendon Formation, St Mellion Formation
Underlies	Holsworthy Group
Overlies	Exmoor Group
Thickness	100 to 720m
Lithology
Primary	mudstones,
Other	cherts, sandstones, limestones, basaltic lavas, tuffs
Location
Region	England
Country	United Kingdom
Extent	north Cornwall through Devon to west Somerset
Type section
Named for	valley of River Teign