The BGS Lexicon of Named Rock Units — Result Details
Exeter Group
Computer Code: | EXE | Preferred Map Code: | EXG |
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Status Code: | Full | ||
Age range: | Cisuralian Epoch (PLC) — Cisuralian Epoch (PLC) | ||
Lithological Description: | Component formations are predominantly breccia, with subordinate sandstone. All formations are alluvial fan deposits. | ||
Definition of Lower Boundary: | Basal formations in Crediton Trough (Cadbury Breccia, Upton Formation, Bow Breccia, Knowle Sandstone) rest unconformably on Bude or Crackington formations. Around and south-west of Exeter, basal formations (Dawlish Sandstone, Whipton Formation, Knowle Sandstone) rest unconformably on Crackington Formation. See definitions of component formations. | ||
Definition of Upper Boundary: | Unconformably overlain by Aylesbeare Mudstone Group. | ||
Thickness: | At least 700m. | ||
Geographical Limits: | From Torbay in the south, north through Newton Abbot to Exeter; all New Red Sandstone strata in the Crediton Trough and probably the Tiverton Trough. | ||
Parent Unit: | New Red Sandstone Supergroup (NRS) | ||
Previous Name(s): | Lower Sandstone And Breccia
(-897)
Lower New Red [Obsolete Name and Code: Use EXE] (-4643) Marginal deposits [Obsolete Name and Code: Use EXE] (-2794) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Area | Group named from the city of Exeter, Devon. | ||
Reference(s): | |||
Henson, M R, 1972. The form of the Permo-Triassic Basin in south-east Devon. Proceedings of the Ussher Society, Vol.3, p.447-457. | |||
Ussher, W A E. 1902. The Geology of the country around Exeter. Memoir of the Geological Survey of Great Britain, Sheet 325. (England and Wales). | |||
Ussher, W A E. 1906. Chapter on Geology. "In" Victoria History of the Counties of England (Devonshire), p.1-48. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E310 E311 E308 E355 E356 E307 E350 |