Computer Code: |
TGR |
Preferred Map Code: |
notEntered |
Status Code: |
Pending Upgrade |
Age range: |
Eifelian Age (DI)
— Eifelian Age (DI) |
Lithological Description: |
Thick sequence mainly of grey, purple and green quartzitic fine- to medium-grained sandstone, commonly parallel laminated and convolute-bedded, with shale and silty shale interbeds. Abundant scoured surfaces and silty drapes. Scattered scarce remains of Psilophyton sp. and a calamitid-like stem. Local distictive facies of deformed laminae of red siltstones and very fine-grained sandstones in which desiccation cracks alternate with convolute laminae. |
Definition of Lower Boundary: |
?Conformable on rocks of the Hollowbrook Member (q.v.). |
Definition of Upper Boundary: |
Overlain ?conformably by rocks of the Rawns Member (q.v.) |
Thickness: |
c.1250m (Tunbridge, 1978). |
Geographical Limits: |
North Devon - west Somerset. |
Parent Unit: |
Hangman Sandstone Formation (HASA)
|
Previous Name(s): |
Trentishoe Grits
(-960)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Cliff sections between Combe Martin Bay and Woody Bay, and between Lynmouth Bay and Minehead. |
Reference(s): |
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). |
Lane, R. 1965. The Hangman Grits - an introduction and stratigraphy. Proceedings of the Ussher Society, Vol.1, 166-167. |
Evans, J W. 1922. The geological structure of the country round Combe Martin. Proceedings of the Geologists' Association, Vol.33, 201-228. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
none recorded or not applicable |