The BGS Lexicon of Named Rock Units — Result Details

Raisby Formation

Computer Code: RML Preferred Map Code: RBY
Status Code: Full
Age range: Guadalupian Epoch (PUG) — Lopingian Epoch (PUL)
Lithological Description: Cream, brown and grey, fine-grained dolostone with grey, fine-grained limestone.
Definition of Lower Boundary: Typically sharp, taken at the incoming of dolostone and limestone above the laminated, bituminous, silty, argillaceous dolostone of the Marl Slate Formation and, where this is absent, either above the aeolian Yellow Sands Formation or unconformably on Carboniferous (usually Coal Measures ) strata.
Definition of Upper Boundary: At the incoming of oolitic and pisolitic or equivalent reef dolostone of the Ford Formation.
Thickness: 48m at type locality; ranges from 20 to 40m but, locally up to 73m in east Durham.
Geographical Limits: Durham Province of English Zechstein; County Durham, Tyne and Wear, Cleveland and northernmost North Yorkshire.
Parent Unit: Zechstein Group (ZG)
Previous Name(s): Lower Magnesian Limestone (-757)
Raisby (Magnesian Limestone) Formation (-4300)
Lower Magnesian Limestone (Durham) [Obsolete Name And Code: Use RML] (LML)
Alternative Name(s): Wetherby Member
Type Section  Raisby Quarry, Nr. Cornforth, County Durham. Smith, et al., 1986. 
Smith, D B and Francis, E A. 1967. Geology of the country between Durham and West Hartlepool. Memoir of the Geological Survey of Great Britain, Sheet 27 (England and Wales). 
Magraw, D, 1975. Permian beds of the offshore and adjacent coastal areas of Durham and south-eastern Northumberland. Journal of the Geological Society of London, Vol.131, 397-414. 
Magraw, D, 1963. The stratigraphy and structure of part of the south-east Durham coalfield. Proceedings of the Yorkshire Geological Society, Vol.34, 153-208. 
Smith, D B, 1994. Geology of the country around Sunderland. Memoir of the British Geological Survey, Sheet 21, (England and Wales). 
Smith, D B, Harwood, G M, Pattison, J and Pettigrew, T H. 1986. A revised nomenclature for Upper Permian strata in eastern England. 9-17 in Harwood, G M and Smith, D B (editors). The English Zechstein and Related Topics. Geological Society Special Publication No.22. 
Smith, D B, 1995. Marine Permian of England. Geological Conservation Review Series No. 8. [London: Chapman and Hall.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E033 E032 E015 E021 E027 E041 E026