The BGS Lexicon of Named Rock Units — Result Details

Abercorris Group

Computer Code: ARO Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Rawtheyan Stage (OW) — Hirnantian Age (OH)
Lithological Description: Weathered dark blue blocky mudstone, well cleaved homogeneous blue mudstone (slate), dark blue micaceous mudstones often sandy or gritty, weathered to a dull bronze.
Definition of Lower Boundary: Drawn at the base of the Red Vein Formation where blue mudstones with orange weathering rest conformably upon mottled mudstones of the Abercwmeiddaw Group.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Narrow Vein Formation where well cleaved slate passes into a dark blue micaceous sandy and gritty mudstone of the Garwedd-Wen Formation.
Thickness: 633 metres approx.
Geographical Limits: Exposed in the area around Corris and Aberllefenni,(Merionethshire).
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Area  Abercorris, North of Corris, Merioneth. 
Pugh, W J. 1923. The geology of the district around Corris and Aberllefenni, (Merionethshire). Quarterly Journal of the Geological Society, London, Vol.79, 508-541. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable