Computer Code: |
HWY |
Preferred Map Code: |
HWY |
Status Code: |
Pending Upgrade |
Age range: |
Rawtheyan Stage (OW)
— Hirnantian Age (OH) |
Lithological Description: |
Grey and dark grey siltstones, muddy siltstones and subordinate parallel laminated sandy siltstones and fine- to medium-grained feldspathic sandstones. Includes locally present basal Hafod Ifan Limestone. |
Definition of Lower Boundary: |
Base unconformable on various Caradoc formations. |
Definition of Upper Boundary: |
top succeeded by pale grey siltstones of the Bron-Y-Graig Formation. |
Thickness: |
450 metres. |
Geographical Limits: |
Not defined. |
Parent Unit: |
Not Entered (?)
|
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 Unpublished PhD Thesis, University of Cambridge.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
|