| Computer Code: |
CMK |
Preferred Map Code: |
Cmk |
| Status Code: |
Full |
| Age range: |
Rhuddanian Age (SR)
— Telychian Age (ST) |
| Lithological Description: |
[Obsolete: use STK] Mudstone and siltstone, black, graptolitic. Mudstones at the base of the formation are calcareous and contain a shelly fauna. Towards the top of the formation calcareous siltstones contain nodules and thin beds of limestone. |
| Definition of Lower Boundary: |
Taken at the base of calcareous mudstone and black graptolitic mudstone that contains a Rhuddanian and Aeronian fauna, overlying mudstone and siltstone of the Sowerthwaite Formation. |
| Definition of Upper Boundary: |
Defined by the base of the overlying Austwick Formation. |
| Thickness: |
Up to 35m |
| Geographical Limits: |
Restricted to the Craven inliers, North Yorkshire. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
Stockdale Shales [Obsolete Name and Code: Use CMK, STK]
(-4556)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
Capple Bank, about 1.5km NNE of Austwick Arthurton et al, 1988 |
| Partial Type Section |
Hunterstye, on the east side of Crummack Dale Arthurton et al, 1988 |
| Reference(s): |
| King, W B R and Wilcockson, W H, 1934. The Lower Palaeozoic rocks of Austwick and Horton-in-Ribblesdale, Yorkshire. Quarterly Journal of the Geological Society of London, Vol.90, 7-31. |
| Arthurton, R S, Johnson, E W, and Mundy, D J C. 1988. Geology of the country around Settle. Memoir of the British Geological Survey, Sheet 60 (England and Wales). |
| Kneller, B C, Scott R W, Soper N J, Johnson E W and Allen P M, 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219-240. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E050
E060
|
