| Computer Code: |
COG |
Preferred Map Code: |
CoG |
| Status Code: |
Full |
| Age range: |
Marsdenian Substage (CZ)
— Marsdenian Substage (CZ) |
| Lithological Description: |
Sandstone, fine-grained, flaggy, feldspathic, with subordinate mudstone, in up to 4 turbiditic cycles. |
| Definition of Lower Boundary: |
The base of the unit is poorly defined. In the field and on stratigraphic logs, the lower boundary is taken at the base of the first sandstone within a sandstone-dominated unit overlying a mudstone-dominated part of the Millstone Grit Group, overlying an unnamed sandstone within the latter; where this is absent the unit is the first sandstone-dominated unit above the mudstone-dominated part of the Millstone Grit Group overlying limestones of the Monsal Dale Limestone Formation. |
| Definition of Upper Boundary: |
The upper boundary is taken at the base of a mudstone-dominated succession of the Millstone Grit Group above sandstones of the Corbar Grit. |
| Thickness: |
200m |
| Geographical Limits: |
Longclough (Cheshire) [SJ 987 737], Whitehills [SJ 973 728] (Cheshire); Edgemoor (Derbyshire) [SK 0343 7345]. |
| Parent Unit: |
Millstone Grit Group [See Also MIGR] (MG)
|
| Previous Name(s): |
Ashover Grit
(ASG)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
A stream section at Kirby Clough (Derbyshire) exposes 3 thin sandstone units from the Corbar Grit (no further details available) (Stevenson and Gaunt, 1971). |
| Partial Type Section |
Disused quarry at Corbar Hill (Buxton, Derbyshire) exposes 20.28m (no further details available) (Aitkenhead et al., 1985). |
| Type Section |
Edgemoor (Derbyshire); natural section exposes 33.53 m (no further details available) (Aitkenhead et al., 1985). |
| Reference(s): |
| Stevenson, I P and Gaunt, G D, 1971. Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 99. |
| Aitkenhead, N, Chisholm, J I, and Stevenson, I P. 1985. Geology of the country around Buxton, Leek and Bakewell. Memoir of the British Geological Survey, England and Wales Sheet 111. |
| Jones, C M, 1980. Deltaic sedimentation in the Roaches Grit and associated sediments (Namurian R2b) in the south-west Pennines. Proceedings of the Yorkshire Geological Society Vol.43, Pt.1, 39-67. |
| Smith, E G, Rhys, G H and Eden, R A. 1967. Geology of the country around Chesterfield, Matlock, and Mansfield. Memoir of the Geological Survey of Great Britain. England and Wales Sheet 112. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E099
E111
|
