The BGS Lexicon of Named Rock Units — Result Details

Abercwmeiddaw Group

Computer Code: ABG Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Rawtheyan Stage (OW) — Rawtheyan Stage (OW)
Lithological Description: Thickly-bedded, mottled, grey-blue mudstones, passing locally into well cleaved slates.
Definition of Lower Boundary: Drawn at the base of the Abercwmeiddaw Group where pale greyish blue, thickly bedded mudstones conformably rest upon black shales of the Nod Glas Formation.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Abercwmeiddaw Group where mottled mudstones pass into blue mudstones with orange weathering of the Red Vein Formation.
Thickness: 450 metres approx.
Geographical Limits: The district 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
Stratotypes:
Type Area  Abercwmeiddaw Quarry, near Corris, Merioneth. 
Reference(s):
Pugh, W. 1923. The geology of the district around Corris and Aberllefeni (Merionethshire). Quarterly Journal of the Geological Society of London, Vol.79, p.512, 520-5. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable