| Computer Code: |
CMU |
Preferred Map Code: |
Cmu |
| Status Code: |
Full |
| Age range: |
Caradoc Series (O4)
— Ashgill Series (OA) |
| Lithological Description: |
Calcareous mudstone with impersistent limestone beds; includes units of sandstone at the base and higher in the succession [Wilsey Beck Sandstone Member]; also of rhyolitic tuff [Cautley Volcanic Member]. |
| Definition of Lower Boundary: |
Not exposed, but taken at the base of the lowest bed of mudstone overlying a small exposure of purple andesite, putatively belonging to the Borrowdale Volcanic Group. |
| Definition of Upper Boundary: |
Taken at the unconformity with the overlying Ashgill Formation. |
| Thickness: |
Up to 570m |
| Geographical Limits: |
Restricted to the Cautley and Dent districts of Cumbria. |
| Parent Unit: |
Dent Group (DNT)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Reference Section |
Backside Beck, Westerdale Inlier, Cautley district, Cumbria Ingham, 1966 |
| Type Section |
Wandale Beck [Murthwaite Inlier] and its tributaries on the western bank between the Odd Gill and the confluence with the River Rawthey, Cumbria Ingham, 1966 |
| Reference(s): |
| Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) |
| Ingham, J K, 1966. The Ordovician rocks in the Cautley and Dent districts of Westmorland and Yorkshire. Proceedings of the Yorkshire Geological Society, Vol.35, 455-505. |
| Owen, A W and Rushton, A W A, 1999. Arenig to Ashgill of northern England. pp 259-292 in Rushton, A W A, Owen, A W, Owens, R M, and Prigmore, J K. British Cambrian to Ordovician stratigraphy. Geological Conservation Review, Vol. 18. Joint Nature Conservation Committee. Peterborough. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E040
E039
E049
|
