| 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 Unpublished PhD Thesis, University of Cambridge.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
|
