Computer Code: |
CWG |
Preferred Map Code: |
CWG |
Status Code: |
Pending Upgrade |
Age range: |
Hirnantian Age (OH)
— Hirnantian Age (OH) |
Lithological Description: |
Coarse grained sandstones, thin siltstones and a locally developed limestone member at the base. Richly fossiliferous. |
Definition of Lower Boundary: |
Base overlies calcareous sandstones of the Dolhir Formation. |
Definition of Upper Boundary: |
Top is succeeded by pale grey siltstones with some interbedded thin sandstones of the Fron Frys Formation. |
Thickness: |
70 metres. Lateral variations, 21 metres - 70 metres. |
Geographical Limits: |
Not defined. |
Parent Unit: |
Dolhir Formation (DO)
|
Previous Name(s): |
Corwen Grit
(-832)
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Wrexham, Sheet 121. |
Reference(s): |
Campbell, S D G. 1983. The geology of an area between Bala and Betws-y-Coed, North Wales. Unpublished PhD Thesis, University of Cambridge. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E120
|