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 Unpublished PhD Thesis, University of Cambridge.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
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