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
|