The BGS Lexicon of Named Rock Units — Result Details

Garwallt Group [Obsolete Name And Code]

Computer Code: GARW Preferred Map Code: notEntered
Status Code: Index Level
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Cleaved blue shales, ash and shales with sporadic ashy shales and thin ashes.
Definition of Lower Boundary: Drawn at base of cleaved blue shales where they rest conformably on calcareous blue mudstones and shales of the Llandeilo Limestone.
Definition of Upper Boundary: Drawn at (possible unconformity) upward passage from shales, ashy shales and ashes to shales and mudstones of the Gwern-feifod Group.
Thickness: Not recorded.
Geographical Limits: Powys, Wales.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Garwallt, Powys, Wales. 
Reference(s):
Wedd, C B, Smith, B, King, W B R and Wray, D A. 1929. Geology of the country around Oswestry. Memoir of the Geological Survey of Great Britain, Sheet 137. 
Cantrill,T C, and others. 1914. Denbighshire and Shropshire district. Summary of Progress of the Geological Survey of Great Britain, for 1914, p.7. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E136