| Computer Code: |
HDL |
Preferred Map Code: |
HDL |
| Status Code: |
Full |
| Age range: |
Rawtheyan Stage (OW)
— Rawtheyan Stage (OW) |
| Lithological Description: |
Bluish-grey biosparite largely comprising cystoid fragments. |
| Definition of Lower Boundary: |
Unconformable on various Caradoc formations. |
| Definition of Upper Boundary: |
Succeeded by siltstones and sporadic thin sandstones of the Hwylfa Formation. |
| Thickness: |
2.3 metres. Lateral variations 0 - 2.5 metres. |
| Geographical Limits: |
Not defined. |
| Parent Unit: |
Hwylfa Formation (HWY)
|
| 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 Unpublished PhD Thesis, University of Cambridge.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
|
