The BGS Lexicon of Named Rock Units — Result Details

New Harbour Formation

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):
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. 
Harris, A L, 1975. A Correlation of Pre-Cambrian Rocks in the British Isles. Geological Society of London Special Report, No.6. 
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. 
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.). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable