| Computer Code: |
CYP |
Preferred Map Code: |
CYP |
| Status Code: |
Index Level |
| Age range: |
Soudleyan Substage (OY)
— Soudleyan Substage (OY) |
| Lithological Description: |
[Obsolete: use CEI] Grey to light-grey variably tuffaceous siltstones and sandy siltstones with a scattered shelly fauna. Occasional discontinuous lithic and crystal tuffs and tuffites occur in the upper 50 metres of the formation. |
| Definition of Lower Boundary: |
Base of siltstones succeeding the acid ash flow tuffs and volcaniclastic sandstones of the Capel Curig Volcanic Formation. |
| Definition of Upper Boundary: |
Siltstones are overlain by a very fossiliferous volcaniclastic sandstone - the Blaen Eidda Member of the Eidda Formation. |
| Thickness: |
220m. Lateral variations 190-220m. |
| Geographical Limits: |
Not defined. |
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Corwen, Sheet 120. |
| 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 Unpublished PhD Thesis, University of Cambridge.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
|
