The BGS Lexicon of Named Rock Units — Result Details

Potts Beck Limestone Formation

Computer Code: PBK Preferred Map Code: PBK
Status Code: Pending Upgrade
Age range: Holkerian Substage (CQ) — Asbian Substage (CR)
Lithological Description: Predominantly limestone but with interbedded sandstone and possibly mudstone. Limestones not only include pale grey biosparites etc, as in Knipe Scar Limestone, but also dark grey, platy beds.
Definition of Lower Boundary: Where medium to dark grey, medium- and coarse-grained limestones and shaly limestones of the Potts Beck Limestone overlie pale, grey-brown, flaggy, fossiliferous limestone of the Ashgill Limestone.
Definition of Upper Boundary: Where pale grey limestone and dark grey limestone and sandstone of the Potts Beck Limestone is overlain by pale grey, scar-forming limestone (mostly thick-bedded biosparites and biopelsparites commonly pseudobrecciated) of the Knipe Scar Limestone.
Thickness: 70 metre. (Thins slightly westward to c.60m north of Orton).
Geographical Limits: Not defined.
Parent Unit: Great Scar Limestone Group (GSCL)
Previous Name(s): Potts Beck Limestone (-1753)
Alternative Name(s): none recorded or not applicable
Type Area  Base at Little Asby Scar on north side of Potts Valley, near Newbiggin-on-Lune, Cumbria. (Sheet 40). 
Type Section  Great Kinmond. 
George, T N, Johnson, G A L, Mitchell, M, Prentice, J E, Ramsbottam, W H C, Sevastopulo, G D and Wilson, R B. 1976. A correlation of the Dinantian rocks of the British Isles. Special Report of the Geological Society of London, No 7. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: