The BGS Lexicon of Named Rock Units — Result Details

Porth y Mor Formation

Computer Code: PYMB Preferred Map Code: notEntered
Status Code: Full
Age range: Lochkovian Age (DO) — Pragian Age (DP)
Lithological Description: Tabular to trough cross-bedded basal conglomerate overlain by cross-laminated to planar laminated, coarse- to fine-grained sandstone and muddy siltstone, occasional beds of impure limestone (calcrete).
Definition of Lower Boundary: Conformably overlain by and/or lateral facies change with Traeth Bach Formation (TRBB) and Bodafon Formation (BODA).
Definition of Upper Boundary: Conformably overlain by Traeth Lligwy Formation (TLL).
Thickness: 345 m.
Geographical Limits: Anglesey.
Parent Unit: Brynrefail Group (BRYF)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
House, M R, Richardson, J B, Chaloner, W G, Allen, J R L, Holland, C H and Westoll, T S. 1977. A Correlation of Devonian rocks of the British Isles. Geological Society of London, Special Report No.8, Scottish Academic Press, Edinburgh. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable