The BGS Lexicon of Named Rock Units — Result Details

Cemlyn Bay Formation

Computer Code: CEML Preferred Map Code: notEntered
Status Code: Full
Age range: Tremadocian Age (OTR) — Floian Age (OFL)
Lithological Description: Chlorite-muscovite schist and phyllite, semipelite and subsidiary psammite, the latter may be volcaniclastic; locally metamorphosed calc-silicate rocks; locally sheet-like units of metamafic rock (amphibolite).
Definition of Lower Boundary: Mainly forming hangingwall to Hen Felin Thrust; in part overlying Porth yr Ysgraf Ophiolitic Formation (PYY).
Definition of Upper Boundary: Unconformably overlain by Ordovician age rocks, eg. Cemaes Group (CMES).
Thickness: none recorded or not applicable
Geographical Limits: Anglesey.
Parent Unit: Llanfechell Group (LFEC)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
none recorded or not applicable
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable