The BGS Lexicon of Named Rock Units — Result Details

Fox Cliff Siltstone Member

Computer Code: FXCL Preferred Map Code: FC
Status Code: Full
Age range: Toarcian Age (JT) — Toarcian Age (JT)
Lithological Description: Mudstone siltstone and silty mudstone, forming two fining upwards cycles, with scattered ferruginous ooids, thin siderite mudstone beds, layers of sideritic concretions and layers of phosphate nodules
Definition of Lower Boundary: Conformable: sharp change up from dark grey mudstone (Peak Mudstone Member)into muddy siltstone, taken at base of semi-continuous sideritic mudstone bed (Bed 57 of Dean, 1954).
Definition of Upper Boundary: Gradational; rapid upward transition from dark grey mudstone and siltstone to paler burrow-mottled silt and sand-rich sediment (Blea Wyke Sandstone Formation).
Thickness: 11.1m at type section, thins to 9.9m 950 m to NW.
Geographical Limits: Cleveland Basin: complete in Peak Trough.
Parent Unit: Whitby Mudstone Formation (WHM)
Previous Name(s): Striatulum Shales (Upper Part) And Grey Beds (Lower Part) (-2809)
Striatulum Clays (-4055)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Fully exposed at the foot of Fox Cliff, Blea Wyke, Ravenscar, North Yorkshire coast, where it is 11.1m thick, Beds 57 to 69 of Dean (1954). Knox, 1984; Simms et al. 2004, pp 271-281. 
Reference(s):
Hesselbo, S P and Jenkyns, H C A, 1995. A comparison of the Hettangian to Bajocian successions of Dorset and Yorkshire. 105-150 in Taylor, P D (Editor). Field geology of the British Jurassic (London Geological Society). 
Rastall, R H and Hemingway, J E. 1949. The Yorkshire Dogger IV. Rosedale and Farndale. Geological Magazine, Vol.86, 201-225, 265-278. 
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. 
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.) 
Young, T P. 1994. The Blea Wyke Sandstone Formation (Jurassic, Toarcian) of Rosedale, North Yorkshire, UK. Proceedings of the Yorkshire Geological Society, Vol. 50, 129-142. 
Rastall, R H and Hemingway, J E. 1941. The Yorkshire Dogger II. Lower Eskdale. Geological Magazine, Vol.78, 351-370. 
Rastall, R H and Hemingway, J E. 1943. The Yorkshire Dogger III. Upper Eskdale. Geological Magazine, Vol.80, 209-230. 
Dean, W T. 1954. Notes on part of the Upper Lias succession at Blea Wyke, Yorkshire. Proceedings of the Yorkshire Geological Society, Vol. 29, 161-179. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable