Computer Code: |
BGR |
Preferred Map Code: |
BGr |
Status Code: |
Full |
Age range: |
Comley Series (EC)
— Merioneth Series (EM) |
Lithological Description: |
Comprises thick bits of coarse-grained green-grey massive sandstone, and interbedded mudstone, which is locally manganiferous, and local conglomerates. |
Definition of Lower Boundary: |
Sharply defined but generally conformable base of coarse conglomeratic sandstone overlying the mudstones of the Llanberis Slates Formation. |
Definition of Upper Boundary: |
Gradational into basal mudstones of the Marchlyn Formation. |
Thickness: |
500m |
Geographical Limits: |
Northern Snowdonia, North Wales. |
Parent Unit: |
Harlech Grits Group (HGG)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
Clogwyn Mawr. |
Partial Type Section |
Roadside exposures towards the southeast end of Llyn Peris, near Llanberis, North Wales. |
Reference(s): |
Howells M F, Reedman A J and Leveridge B E. 1985. Geology of the country around Bangor: Explanation for 1:50 000 geological sheet 106 (England and Wales). British Geological Survey Sheet Explanation. [London: HMSO.] 34pp. |
Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
E119
E106
E118
|