| Computer Code: |
HNA |
Preferred Map Code: |
HNA |
| Status Code: |
Pending Upgrade |
| Age range: |
Arenig Series (OR)
— Arenig Series (OR) |
| Lithological Description: |
Light grey feldspathic sandstones. Rare large-scale cross-bedding. Locally muddy and strongly bioturbated. Rich shelly fauna. |
| Definition of Lower Boundary: |
Base contrasts with flaggy laminated siltstones and sandstones below. |
| Definition of Upper Boundary: |
Top marked by incoming of mudstone. |
| Thickness: |
190 metres. Lateral variations 20 - 190 metres. |
| Geographical Limits: |
Not defined. |
| Parent Unit: |
Allt Lwyd Formation (ALL)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Bala, Sheet 136. |
| Reference(s): |
| Fearnsides, W G. 1905. On the geology of Arenig and Moel Llyfnant. Quarterly Journal of the Geological Society, Vol. 61, 608-640. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E120
|
