The BGS Lexicon of Named Rock Units — Result Details

Rhiwlas Limestone Member

Computer Code: RWL Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Ashgill Series (OA) — Ashgill Series (OA)
Lithological Description: Impersistent, locally honeycombed, fine-grained, pale grey, muddy bioclastic limestone with mudstone partings.
Definition of Lower Boundary: Locally unconformable on various Caradoc strata.
Definition of Upper Boundary: Conformable upward passage into the mudstones of the main part of the Moelfryn Mudstone Formation.
Thickness: To 5m
Geographical Limits: Data not available.
Parent Unit: Moelfryn Mudstones Formation (MFN)
Previous Name(s): Rhiwlas Limestone Formation (-3013)
Rhiwlas Limestone (-3655)
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
Bassett, D A, Whittington, H B and Williams, A. 1966. The stratigraphy of the Bala district, Merionethshire. Quarterly Journal of the Geological Society of London, Vol.122, 219-271. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E136 E120