The BGS Lexicon of Named Rock Units — Result Details
Middle Grit [Obsolete: use MARSD]
| Computer Code: | MGT | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Index Level | ||
| Age range: | Marsdenian Substage (CZ) — Marsdenian Substage (CZ) | ||
| Lithological Description: | [Obsolete: use MARSD] Sandstone overlain by fireclays or ganisters. Coal seams are locally conspicuous and marine bands are well developed. Shale and gritstone also occur. | ||
| Definition of Lower Boundary: | Drawn at base of marine band containing Bilinguites gracilis where it rests conformably on grits of Kinderscoutian age. | ||
| Definition of Upper Boundary: | Drawn at conformable upward passage from a marine band containing Gastrioceras Cancellatum to shales of the Rough Rock Group. | ||
| Thickness: | Up to approximately 360 metres. | ||
| Geographical Limits: | North England:- Yorkshire, Lancashire, Derbyshire, Staffordshire. | ||
| Parent Unit: | none recorded or not applicable | ||
| Previous Name(s): | Middle Grit Group [Obsolete Name and Code: Use MARSD, MGT]
(-2310)
Middle Grits [Obsolete Name and Code: Use MGT] (-1694) |
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| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | North of England. (The grid reference SJ 33 000, 55 000, covers the National Grid areas SD, SE, SJ, SK). | ||
| Reference(s): | |||
| Wray, D A et al, 1930. Geology of the country around Huddersfield and Halifax. Memoir of the Geological Survey of Great Britain. | |||
| Hudson, R G S and Dunnington, H V, 1939. A boring in the Lower Coal Measures and Millstone Grit at Bradford. Proceedings of the Yorkshire Geological Society, Vol.24, p.132. | |||
| Green, A H and others. 1866. One-inch Old Series Sheet 81 NE. Geological Survey of Great Britain. | |||
| Green, A H and others. 1878. Yorkshire Coalfield. Memoirs of the Geological Survey of Great Britain, 27-33. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||