The BGS Lexicon of Named Rock Units — Result Details

Grey Sandstone Member

Computer Code: GSDT Preferred Map Code: GS
Status Code: Full
Age range: Toarcian Age (JT) — Toarcian Age (JT)
Lithological Description: Sandstone, grey, very fine- to fine-grained, muddy coarsening upwards to silty, with interbeds of muddy siltstone, all micaceous, and subordinate thin beds of silty mudstone. Sandstone and siltstone beds include sideritic concretions and lenses that weather reddish, mudstone beds in the basal part include small phosphate nodules. Bioturbated throughout with paler burrow fills, 'nests' of shells, especially bivalves, and common belemnites.
Definition of Lower Boundary: Gradational; rapid upward transition from dark grey mudstone of the Whitby Mudstone Formation to paler burrow-mottled silt and sand-rich sediment.
Definition of Upper Boundary: Sharp change up from grey-weathering sandstone to yellow-weathering sandstone of Yellow Sandstone Member (Blea Wyke Sandstone Formation) which corresponds with the base of a well-defined upward-coarsening cycle.
Thickness: 7.8 to 9.0m
Geographical Limits: Restricted to the 'Peak Trough' of the Cleveland Basin: crops out onshore only on the foreshore and cliffs between Peak Steel and Blea Wyke Point, Ravenscar, North Yorkshire.
Parent Unit: Blea Wyke Sandstone Formation (BW)
Previous Name(s): Grey Sands (-296)
Grey Beds (GRY)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Fully exposed in northern cliff face of Blea Wyke Point, Ravenscar, North Yorshire. Knox, 1984; Simms et al. 2004, pp 271-281. 
Reference(s):
Fox-Strangways, C and Barrow, G, 1915. The geology of the country between Whitby and Scarborough (2nd edition). Memoir of the Geological Survey of the United Kingdom. 
Knox, R W O B. 1984. Lithostratigraphy and depositional history of the late Toarcian sequence at Ravenscar, Yorkshire. Proceedings of the Yorkshire Geological Society, Vol. 45, 99-108. 
Riding, J B. 1984. A palynological investigation of Toarcian to early Aalenian strata from the Blea Wyke area, Ravenscar, North Yorkshire. Proceedings of the Yorkshire Geological Society, Vol. 45, 109-122. 
Buckman, S S. 1915. A palaeontological classification of Jurassic rocks of the Whitby district; with a zonal table of Lias ammonites. The geology of the country between Whitby and Scarborough. Memoir of the Geological Survey of the United Kingdom, (2nd edition). Fox-Strangways, C, and Barrow, G (editors). 
Simms, M J, Chidlaw, N, Morton, N, and Page, K N. 2004. British Lower Jurassic Stratigraphy. Geological Conservation Review Series. No. 30. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E044