The BGS Lexicon of Named Rock Units — Result Details

Screes Gill Formation

Computer Code: SGI Preferred Map Code: notEntered
Status Code: Full
Age range: Ludlow Epoch (SU) — Ludlow Epoch (SU)
Lithological Description: Thin, medium or thick beds of fine-grained sandstone grading up to mudstone, intercalated with thin-bedded siltstone-mudstone couplets, and laminated siltstone units.
Definition of Lower Boundary: Below the first sandstone bed above the laminated siltstone of the Wray Castle Formation.
Definition of Upper Boundary: Below a 70m thick siltstone-dominated unit, forming the basal division of the 'Undivided Coniston Group'.
Thickness: About 280m in the type section.
Geographical Limits: Unit, as defined, is recognised in the southern and central Howgill Fells (Sheet SD69). Correlation with lower part of Coniston Group in the northern Howgills is probable, but as yet unproven.
Parent Unit: Coniston Group (CTG)
Previous Name(s): Lower Coniston Grits (-4878)
Lower Coniston Grits (Part) (-3669)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Continuous dry stream section in Screes Gill and overlying crags. 
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. 
Dakyns, J R, et al, 1891. The geology of the country around Mallerstang, with parts of Wensleydale, Swaledale and Arkendale. Memoir of the Geological Survey of England and Wales. 
Rickards, R B, 1967. The Wenlock and Ludlow succession in the Howgill Fells (north-west Yorkshire and Westmorland). Quarterly Journal of the Geological Society, Vol.123, 215-251. 
King, L M. 1992. A basin study of the early Palaeozoic Windermere Group, northwest England. Unpublished PhD thesis. University of Cambridge. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable