The BGS Lexicon of Named Rock Units — Result Details

Dog Crag Tuff Member

Computer Code: DCT Preferred Map Code: DCT
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Eutaxitic lapilli-tuff, composition probably dacitic (or andesitic), interpreted as pyroclastic flow deposit.
Definition of Lower Boundary: Base of lapilli-tuff rests on a non-sequence that occurs at the top of the Whinny Bank Formation - an interbedded succession of siltstone and andesitic lapilli-tuff.
Definition of Upper Boundary: Parallel bedded tuff and lapilli-tuff of the Po House Tuff Formation.
Thickness: To 30m
Geographical Limits: Wicham Valley:- between Bankside (SD 158 831) and Lacra Bank (SD 145 815)
Parent Unit: Po House Tuff Formation (PHT)
Previous Name(s): Po House Tuffs (Part) (-857)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Dog Crag, Po House Bank, Whicham Valley, Cumbria. 
Reference(s):
Mathieson, N A, 1986 Geology, structure and geochemistry of the Ordovician volcanic succession in south west Cumbria. Unpublished Ph.D. thesis, University of Sheffield. 
Green, J F N, 1913. The older Palaeozoic succession of the Dudden Estuary. London, 23pp. 
British Geological Survey 1994a. Silecroft, SD18SW solid and drift 1:10,000 (Keyworth, Nottingham, British Geological Survey). 
British Geological Survey, 1994(b). Millom Park, SD18SE, Solid and Drift, 1:10,000 (Keyworth, Nottingham, British Geological Survey). 
Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E048