The BGS Lexicon of Named Rock Units — Result Details

Penmon Limestone Formation [Obsolete Name And Code: Use LGHL]

Computer Code: PEL Preferred Map Code: notEntered
Status Code: Index Level
Age range: Asbian Substage (CR) — Asbian Substage (CR)
Lithological Description: Massive to rubbly pale skeletal limestones with intercalated ochreous weathering, thin, clay palaeosol horizons; a widely recognised 3m-thick shale bed occurs 20m above the base of the formation.
Definition of Lower Boundary: Lower contact taken at the top of the uppermost porcellanous limestone of the Bryn Tirion Member.
Definition of Upper Boundary: Upper contact taken at the palaeosol immediately below the lowest argillaceous units of the succeeding Traeth Bychan Limestone.
Thickness: 75m
Geographical Limits: Not defined.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  Penmon and Flagstaff Quarries, Sheet 94. 
Power, G M. Not published. The Stratigraphy and Sedimentology of the Lower Carboniferous in Anglesey, with special reference to rocks of Asbian(DI) age. Ph.D. Thesis, Queen's University, Belfast, 1977. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: