The BGS Lexicon of Named Rock Units — Result Details

Gaerfawr Group [Obsolete Code: Use GAFA]

Computer Code: GGP Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Longvillian Substage (OL) — Longvillian Substage (OL)
Lithological Description: Greenish micaceous grits with some shales.
Definition of Lower Boundary: Drawn at the base of the Gaerfawr Group where green micaceous grit conformably rests upon shales of the Pwll-y-Glo Group.
Definition of Upper Boundary: Drawn at the conformable upward passage of micaceous grit to black phosphate shales of the Gwern-y-Brain Group.
Thickness: 330 metres approx.
Geographical Limits: Gaerfawr Hill, north-west of Welshpool, Powys.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Gaerfawr Hill, north west of Welshpool. 
Reference(s):
Bancroft, B B, 1933. Correlation Tables of the stages Costonian - Onnian in England and Wales. Published by the author, Blakeney, Glos. 
Wade, A, 1911. The Llandovery and associated rocks of north-eastern Montgomeryshire. Quarterly Journal of the Geological Society of London. Vol.67, p.419,428-431. 
Shackleton, R M, 1938. The geology of the district around Llansantffraid Ym Mechain, Montgomeryshire. Quarterly Journal of the Geological Society of London. Vol.94, p.455. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable