| Computer Code: |
NNH |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Furongian Epoch (EF)
— Tremadocian Age (OTR) |
| Lithological Description: |
Chlorite-muscovite schist and phyllite, semipelite predominates with subsidiary psammite. Metabasaltic rock and calcsilicate rock locally. Abundant sheet-like units of metamafic rock (amphibolite) occur locally. |
| Definition of Lower Boundary: |
Conformably upon the Rhoscolyn Formation (NSR). |
| Definition of Upper Boundary: |
Unconformity with the Cemaes Group (CMES). |
| Thickness: |
2000 m. |
| Geographical Limits: |
Western and northern parts of Anglesey and eastern Holy Island. |
| Parent Unit: |
Holy Island Group (NHI)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
New Harbour area, Holyhead, Anglesey. |
| Reference(s): |
| Greenly, E. 1919. The geology of Anglesey, Vol 1. Memoir of the Geological Survey of Great Britain (England and Wales). (London: H.M.S.O.). |
| Treagus, J E, Treagus, S H, and Woodcock, N H. 2013. The significance of the boundary between the Rhoscolyn and New Harbour formations on Holy Island, North Wales, to the deformation history of Anglesey. Geological Magazine, 150(3), 519-535. |
| Harris, A L, 1975. A Correlation of Pre-Cambrian Rocks in the British Isles. Geological Society of London Special Report, No.6. |
| Shackleton, R M, 1954. The structure and succession of Anglesey and the Lleyn Peninsula. British Association for the Advancement of Science, Vol.11, p.106-108. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
