| Computer Code: |
ADM |
Preferred Map Code: |
ADM |
| Status Code: |
Index Level |
| Age range: |
Soudleyan Substage (OY)
— Soudleyan Substage (OY) |
| Lithological Description: |
[Obsolete: use CSW] Silty mudstones and fine-grained siltstones. |
| Definition of Lower Boundary: |
Overlies Glyn Gower Siltstones, or Frondderw Tuff where this is developed. |
| Definition of Upper Boundary: |
Overlain by Pont-y-ceunant Ash at base of Gelli-Grin Calcareous Ashes. |
| Thickness: |
c.400m. |
| Geographical Limits: |
none recorded or not applicable
|
| Parent Unit: |
none recorded or not applicable
|
| Previous Name(s): |
Allt Ddu Mudstones [Obsolete Name and Code: Use ADM]
(-3155)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| none recorded or not applicable |
| 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 Unpublished PhD Thesis, University of Cambridge.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
E136
|
