| Computer Code: |
PDM |
Preferred Map Code: |
PM |
| Status Code: |
Full |
| Age range: |
Arenig Series (OR)
— Arenig Series (OR) |
| Lithological Description: |
Dominantly coarse-grained, locally conglomeratic, bioturbated sandstones, with minor mudstone. |
| Definition of Lower Boundary: |
Underlain unconformably by interlaminated sandstone and mudstone of the Ceiriad Formation (Mawddach Group). |
| Definition of Upper Boundary: |
Overlain gradationally by thickly bedded pale-weathering sandstones of the Trwyn yr Wylfa Member (St Tudwals Formation). |
| Thickness: |
15 to 37m |
| Geographical Limits: |
Pwllheli area, northwest Wales. |
| Parent Unit: |
St Tudwal's Formation (STUD)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Pared Mawr, in the area near Pwllheli. |
| Reference(s): |
| Young, T P, Gibbons, W and McCarroll, D. 2002. Geology of the country around Pwllheli. Memoir of the British Geological Survey, Sheet 134 (England and Wales). |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E134
|
