Computer Code: |
EI |
Preferred Map Code: |
EI |
Status Code: |
Index Level |
Age range: |
Longvillian Substage (OL)
— Longvillian Substage (OL) |
Lithological Description: |
[Obsolete: use CEI] Yellow-grey to grey and greenish-grey sandy-siltstones, fine-grained sandstones and subordinate siltstones. Includes Blaen Eidda Member at its base and a laharic debris flow towards its top. It is highly fossiliferous. |
Definition of Lower Boundary: |
Volcaniclastic green fossiliferous sandstone (Blaen Eidda Member) overlies grey siltstones and fine-grained sandstones of the Carn-y-Parc Formation. |
Definition of Upper Boundary: |
Overlain by ash-flow tuff of the Lower Crafnant Volcanic Formation. |
Thickness: |
50 metres. Lateral variations 0-50 metres. |
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 Unpublished PhD Thesis, University of Cambridge.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
|