| Computer Code: |
HGG |
Preferred Map Code: |
HGG |
| Status Code: |
Full |
| Age range: |
Comley Series (EC)
— St David's Series (ED) |
| Lithological Description: |
Sandstones, mudstones and turbiditic siltstones, conglomerates and manganese ore beds. See component formations (in descending order: Gamlan, Barmouth, Hafotty, Rhinog, Llanbedr, Dolwen) for detailed account of lithologies. |
| Definition of Lower Boundary: |
Not exposed in core of Harlech Dome but proved resting on Bryn Teg Volcanic rocks in Bryn Teg borehole. |
| Definition of Upper Boundary: |
Base of Clogau Formation (Mawddach Group). |
| Thickness: |
Approximately 2000m |
| Geographical Limits: |
Exposed in the central area of the Harlech Dome. |
| Parent Unit: |
Not Applicable (-)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Exposed over the area between Harlech, Barmouth and Trawsfynydd. See entries for Gamlan, Barmouth, Hafotty, Rhinog, Lanbedr and Dolwen formations. |
| Type Area |
Harlech Dome. |
| 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. |
| Matley, C A and Wilson, T S. 1946. The Harlech Dome, North of the Barmouth Estuary. Quarterly Journal of the Geological Society of London, Vol.102, 1-40. |
| 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. |
| Whittard, W F and Simpson, S, (Editors), 1958. Lexique Stratigraphique International, Europe, Part 3a III, Cambrian. |
| Cowie, J W, Rushton, A W A, and Stubblefield, C J. 1972. A correlation of Cambrian rocks in the British Isles. Special Report of the Geological Society of London, No. 2, p. 26. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E119
E135
E149
|
