Exeter Group

The Exeter Group is a Permian lithostratigraphic group (a sequence of rock strata) which occurs through East Devon in southwest England. The name is derived from the city of Exeter in Devon which is partly underlain by rocks of this age.[1]

Exeter Group
Stratigraphic range: Cisuralian
Cross-bedded sandstone of the Dawlish Sandstone Formation, near Dawlish
TypeGroup
Unit ofNew Red Sandstone Supergroup
UnderliesAylesbeare Mudstone Group
OverliesHolsworthy Group
Lithology
Primarybreccia
Othersandstone
Location
Regionsouthwest England
CountryEngland
Extenteast Devon
Type section
Named forExeter

Outcrops

These rocks are found along the coast of East Devon and northwards to the Tiverton trough.[2]

Lithology and stratigraphy

The Group comprises over 700m of sedimentary breccias with subordinate sandstones. It is divided into numerous formations: the Dawlish Formation, Monkerton Formation, Heavitree Breccia, Alphington Breccia, Whipton Formation, Knowle Sandstone, Shute Sandstone, Yellowford Formation, Crediton Breccia, Thorverton Sandstone, Cadbury Breccia, Newton St Cyres Formation, Creedy Park Sandstone, and Bow Breccia. The Cadbury Breccia may be Carboniferous in age.[3] The Wytch Farm Breccia proved in a borehole to the east is also assigned to the Group.[4]

References
  1. http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=EXE (BGS on-line lexicon of rock units)
  2. British Geological Survey 1:625,000 scale Bedrock geology UK South sheets
  3. British Geological Survey 1:50,000 scale geological map (England) sheet 325, Exeter
  4. British Geological Survey 1:50,000 scale geological map (England) sheet 327, Bridport
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