The BGS Lexicon of Named Rock Units — Result Details
Hangman Sandstone Formation
Computer Code: | HASA | Preferred Map Code: | HaS |
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Status Code: | Full | ||
Age range: | Eifelian Age (DI) — Givetian Age (DV) | ||
Lithological Description: | Mainly sandstone, purple, grey and green, commonly thick-bedded and parallel laminated, locally convolute-bedded or cross-bedded, fine- to medium-grained. Interbeds of cleaved shale, siltstone and silty very fine-grained sandstone, and some thicker units of cleaved purple mudstone interlaminated with very fine-grained sandstone. Minor local developments of conglomerate and pebbly sandstone, stratigraphical position uncertain. Divided into five units by Tunbridge (1978). | ||
Definition of Lower Boundary: | Conformable on Lynton Formation. Boundary taken where sandstones become dominant in upward succession. | ||
Definition of Upper Boundary: | Commonly faulted but probably conformable with Ilfracombe Slates. | ||
Thickness: | 1097m (Evans, 1922). 1350m (Lane, 1965). 1658m (Tuunbridge, 1978). 2000-2500m (Edmonds et al. 1985). | ||
Geographical Limits: | North Devon - west Somerset coasts (sheets 277 and 278). | ||
Parent Unit: | Not Applicable (-) | ||
Previous Name(s): | Upper Hangman Grits [Obsolete Name And Code: See HASA]
(UPH)
Hangman Grits [Obsolete Name And Code: Use HASA] (HAG) Hangman Sandstone Group [Obsolete Name And Code: See HASA] (HGMS) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Partial Type Section | Cliff sections between Lynmouth Bay, Lynmouth and Minehead. | ||
Partial Type Section | Cliff sections between eastern end of Wild Pear Beach, Combe Martin and Ramsey Beach, west of Heddon's Mouth. | ||
Reference(s): | |||
Etheridge, R. 1867. On the physical structure of west Somerset and north Devon and on the palaeontological value of the Devonian fossils. Quarterly Journal of the Geological Society of London, Vol. 23, p.568-698. | |||
Edmonds, E A, Whittaker, A, and Williams, B J. 1985. Geology of the country around Ilfracombe and Barnstaple. Memoir of the British Geological Survey, Sheets 277 and 293 (England and Wales). | |||
Tunbridge, I P. 1978. North Devon - Lower and Middle Devonian: Hangman Sandstone Group. 9-13 in Scrutton, C T (Editor), A field guide to selected areas of the Devonian of south-west England. International Symposium on the Devonian System. (PADS 78). (Palaeontological Association). | |||
Evans, J W. 1922. The geological structure of the country round Combe Martin. Proceedings of the Geologists' Association, Vol.33, 201-228. | |||
Lane, R. 1965. The Hangman Grits - an introduction and stratigraphy. Proceedings of the Ussher Society, Vol.1, 166-167. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E277 E279 |