The BGS Lexicon of Named Rock Units — Result Details

Five Yard Limestone Member

Computer Code: FYL Preferred Map Code: FYL
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: Limestone, dark grey, argillaceous, becoming grey compact towards base. In the south, fine-grained with thin evenly bedded mudstone parting with many fossils. In the north, becoming increasingly crinoidal and locally characterised by coarse crinoidal debris. Intercalated thin unit (to 2.1m) of black fossiliferous calcareous mudstone, which divides the member into two parts. Styolitic particularly near base (Johnson et al, 1996). On Dun Fell the limestone has yielded goniatites indicating the P2b biozone (Johnson and Dunham, 1963).
Definition of Lower Boundary: Taken at the sharp base of limestone overlying measures within the Alston Formation; directly underlain by burrowed, current and ripple-bedded, medium-grained sandstone; a thin coal is present in places.
Definition of Upper Boundary: Taken at base of the overlying mudstone within measures of the Alston Formation.
Thickness: 3 to 8.5m
Geographical Limits: Member within the Alston Formation of the Alston and Lake District blocks in Cumbria, Northumberland and Durham, lying stratigraphically between the Scar (below) and the Three Yard (above) limestone members. Possibly correlated with the Eelwell Limestone of the Northumberland Trough. Also present in the northern part of the Askrigg Block and in the Stainmore Trough. Well exposed along the Pennine escarpment, in Teesdale and Weardale.
Parent Unit: Alston Formation (AG)
Previous Name(s): Five Yard Limestone (-3412)
Alternative Name(s): Eelwell Limestone
Stratotypes:
Type Section  Lunchy Beck, northern tributary of Croglin Water, Cumbria. Arthurton and Wadge (1981. 
Reference Section  Rookhope Borehole (BGS Reg No NY94SW1). Johnson and Nudds (1996). 
Reference(s):
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. 
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. 
Johnson, G A L, Nudds, J R and Robinson, D. 1980. Carboniferous stratigraphy and mineralisation at Ninebanks, West Allendale, Northumberland. Proceedings of the Yorkshire Geological Society, Vol.43, 1-16. 
Johnson, G A L and Dunham, K C. 1963. The geology of Moor House. Monographs of the Nature Conservancy No.2. 
Trotter, F M and Hollingworth, S E. 1932. The geology of the Brampton District. Memoir of the Geological Survey, Sheet 18. 
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. 
Arthurton, R S, and Wadge, A J. 1981. Geology of the country around Penrith. Memoir for geological sheet 24. Institute of Geological Sciences, London, HMSO. 
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). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E050 E040 E032 E041 E051 E031 E025 E024 E020 E018 E023 E026 E019 E030