The BGS Lexicon of Named Rock Units — Result Details

Coldwell Formation

Computer Code: CDW Preferred Map Code: Cdw
Status Code: Full
Age range: Wenlock Epoch (SW) — Ludlow Epoch (SU)
Lithological Description: Comprises a lower unit of heavily bioturbated, calcareous siltstone with subordinate laminated muddy siltstones, which is the Randy Pike Member, overlain by laminated hemipelagite and then another unit of calcareous siltstone with laminated muddy siltstone in the upper part , which is the High Cross Member.
Definition of Lower Boundary: Conformably overlies the Birk Riggs Formation.
Definition of Upper Boundary: Conformably overlain by the Wray Castle Formation.
Thickness: From 55m to 80m
Geographical Limits: Occurs towards the base of the Windermere Supergroup and crops out as a narrow strip across the southeastern part of the Lake District from Millom to east of Windermere. It also occurs south of the Kirkby Fault in Furness, and in the Howgill Fells.
Parent Unit: Tranearth Group (TNTH)
Previous Name(s): Coldwell Beds (-3288)
Coldwell Beds And Horton Flags [Obsolete Name And Code: See CDW And HNF] (CBHF)
Coldwell Formation (CDW)
Middle Coldwell Beds [Obsolete Name And Code: Within CDW] (MCW)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Birk Riggs. Kneller, 1990. 
Reference(s):
Kneller, B C. 1990. The Wenlock rocks of sheet 38 (Ambleside). British Geological Survey Technical Report, WA/90/64 
Arthurton, R S, Johnson, E W and Mundy, D J C. 1988. Geology of the country around Settle. Memoir of the British Geological Survey, Sheet 60 (England and Wales). 
Kneller, B C, Scott R W, Soper N J, Johnson E W and Allen P M, 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219-240. 
Moseley F. 1984. Lower Palaeozoic lithostratigraphical classification in the English Lake District. Geological Journal, Vol. 19, p. 239-247. 
Marr J E. 1892. On the Wenlock and Ludlow strata of the Lake District. Geological Magazine, Vol. 9, p 534-541. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E039 E038 E048