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):
Cantrill,T C, and others. 1914. Denbighshire and Shropshire district. Summary of Progress of the Geological Survey of Great Britain, for 1914, p.7. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E136