The BGS Lexicon of Named Rock Units — Result Details

Jew Limestone Member

Computer Code: JWL Preferred Map Code: JWL
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: Limestone, bioclastic, dark grey, thick wavy beds with fissile mudstone parting, and usually with abundant fossils. At many localities it contains a Saccaminopsis band about two thirds of the thickness above the base (Burgess and Holliday, 1979). A complete section is recorded from the Rookhope Borehole, but the lower 5m are intensely mineralized, whereas the upper part is black crinoidal limestone (Johnson and Nudds, 1996). In Cumbria, the member is composed of pale porcellaneous limestone with spots at the base, overlain by well bedded grey and grey-blue limestone that is crowded with Saccaminopsis fusulinaformis, and in some beds with abundant "Lithostrotion" (Eastwood et al., 1968).
Definition of Lower Boundary: Taken at the sharp base of limestone beds, overlying a generally conformable ganister sandstone of the Alston Formation, or north of the Lake District resting on a few metres of siltstone, mudstone and sandstone.
Definition of Upper Boundary: Overlain, generally conformably, by siltstone and mudstone of the Alston Formation.
Thickness: Varies between 5 and 9.5m on the Alston Block; 9.1 to 12.2m north of the Lake District massif.
Geographical Limits: Exposed on the North Pennine escarpment, on the northern flanks of the Lake District massif and in the Vale of Eden, and in Teesdale, Cumbria; also in Weardale, Durham, in the Cowgreen-Maizebeck area and was formerly seen on the site of the Burnhope reservoir in Weardale.
Parent Unit: Alston Formation (AG)
Previous Name(s): Jew Limestone (-987)
Alternative Name(s): Oxford Limestone
Stratotypes:
Reference Section  Roadside quarry, 730m east 25 degrees north of the church in Uldate, Cumbria. Eastwood et al., 1968. 
Type Section  Force Burn, about 1.2km upstream from its confluence with the River Tees, just above the Cow Green Reservoir,Teesdale, Cumbria. Johnson and Dunham (1963) 
Reference(s):
Trotter, F M and Hollingworth, S E. 1932. The geology of the Brampton District. Memoir of the Geological Survey, Sheet 18. 
Johnson, G A L and Dunham, K C. 1963. The geology of Moor House. Monographs of the Nature Conservancy No.2. 
Dunham, K C. 1990. Geology of the Northern Pennine Orefield, Vol.1. Tyne to Stainmore, (2nd edition) Economic Memoir of the British Geological Survey, Sheets 19 and 25, parts of 13, 24, 26, 31, 32 (England and Wales). 
Burgess, I C and Holliday, D W. 1979. Geology of the country around Brough-under-Stainmore. Memoir for 1:50 000 geological sheet 31 and parts of sheets 25 and 30. Geological Survey of Great Britain (England and Wales). [London: HMSO.] 131pp. 
Johnson, G A L and Nudds, J R. 1996. Carboniferous biostratigraphy of the Rookhope Borehole, Co. Durham. Transactions of the Royal Society of Edinburgh: Earth Sciences, Vol.86, 181-226. 
Eastwood,T, Hollingworth, S E, Rose, W C C and Trotter, F M. 1968. Geology of the country around Cockermouth and Caldbeck. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 23. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E031 E024 E020 E040 E018 E023 E026 E025 E030