The BGS Lexicon of Named Rock Units — Result Details

Hollowbrook Member

Computer Code: HOB Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Emsian Age (DE) — Eifelian Age (DI)
Lithological Description: Mainly sandstone, grey, quartzitic, clean, parallel-laminated, with inter-bedded cross-laminated units and some mudstone interbeds. Ladder ripples and reactivation surfaces are present. Local channels filled with flaser and lenticular beds. Trace fossil Arenicolites and Tentaculitids.
Definition of Lower Boundary: Conformable on rocks of the Lynton Formation (q.v.).
Definition of Upper Boundary: Overlain ?conformably by rocks of the Trentishoe Member (q.v.).
Thickness: 70m (Tunbridge, 1978)
Geographical Limits: North Devon - west Somerset
Parent Unit: Hangman Sandstone Formation (HASA)
Previous Name(s): Trentishoe Grits (-960)
Hollowbrook Formation (-4097)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Cliff top exposures at Hollowbrook, about 1.5km west of Woody Bay, near Lynton, North Devon. 
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