Computer Code: |
MWG |
Preferred Map Code: |
MWG |
Status Code: |
Full |
Age range: |
St David's Series (ED)
— Tremadoc Series (O1) |
Lithological Description: |
Mudstone (including dark grey of black mudstone), siltstone and sandstone. For details of specific lithologies refer to entries for the Dol-cyn-Afon, Dolgellau, Ffestiniog Flags, Maentwrog and Clogau formations. |
Definition of Lower Boundary: |
Base of the Clogau Formation as originally proposed, but under discussion. |
Definition of Upper Boundary: |
Top of the Dol-cyn-Afon Formation. |
Thickness: |
c.2400m |
Geographical Limits: |
Harlech Dome and southern Snowdonia. |
Parent Unit: |
Not Applicable (-)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Area |
From Criccieth east towards Ffestiniog, south to Dolgellau and southwest of Arthog. See also stratotypes for Clogau, Maentwrog, Ffestiniog Flags, Dolgellau and Dol-cyn-Afon formations. |
Reference(s): |
Allen, P M, and Jackson, A A. 1985. Geology of the country around Harlech. Memoir of the British Geological Survey, Sheet 135 with part of Sheet 149 (England and Wales). (London: HMSO.) 112 pp. |
Allen, P M, Jackson, A A, and Rushton, A W A. 1981. The stratigraphy of the Mawddach Group in the Cambrian succession of North Wales. Proceedings of the Yorkshire Geological Society, Vol. 43, 295-329. |
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
E149
E118
|