The BGS Lexicon of Named Rock Units — Result Details

Stockdale Group

Computer Code: STK Preferred Map Code: Stk
Status Code: Full
Age range: Hirnantian Age (OH) — Telychian Age (ST)
Lithological Description: Includes Skelgill and Browgill Formations as separately defined: dominantly mudstone and siltstone.
Definition of Lower Boundary: As for base of Skelgill Formation: unconformably overlies the Red Gill Formation of the Dent Group or conformable (but with local non-sequence) at base of graptolitic black mudstone and siltstone above calcareous and bioturbated siltstone of the Dent Group (Ashgill Formation).
Definition of Upper Boundary: Conformable, at top of pale green oxic siltstones (Browgill Formation); overlain by laminated siltstone (Brathay Formation).
Thickness: 50 - 130m
Geographical Limits: Southern Lake District and Lower Palaeozoic Inliers of Northern England.
Parent Unit: Windermere Supergroup (WIN)
Previous Name(s): Stockdale Group [Obsolete Code: Use STK] (SCSH)
Stockdale Shales (-4556)
Alternative Name(s): Stockdale Subgroup
Stratotypes:
Type Area  Stockdale Beck. Reference Sections are as defined for the component Skelgill and Browgill formations. 
Reference(s):
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. 
Cocks, L R M, Holland, C H and Rickards, B. 1992. A revised correlation of Silurian rocks in the British Isles. Geological Society of London Special Report. No.21, 32pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E038 E040 E048 E039