The BGS Lexicon of Named Rock Units — Result Details

Roch Rhyolitic Group [Obsolete Name And Code: Use RRH]

Computer Code: PRR Preferred Map Code: RRh
Status Code: Index Level
Age range: Ordovician Period (O) — Ordovician Period (O)
Lithological Description: Rhyolitic lavas and flinty rhyolitic tuffs.
Definition of Lower Boundary: Not defined.
Definition of Upper Boundary: Not defined.
Thickness: Not defined.
Geographical Limits: 1:50,000 Sheet 209 (St Davids) and adjacent Sheet 210.
Parent Unit: Not Entered (?)
Previous Name(s): Trefgarn Rhyolitic Series (-1774)
Roch Rhyolitic Series (-3624)
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
Thomas, H H, and Cox, A H. 1924. The Volcanic Series of Trefgarn, Roch and Ambleston (Pembrokeshire). Quarterly Journal of the Geological Society, Vol.80, p.520-548. 
Shackleton, R M. 1975. Precambrian rocks of Wales. 76-83 in A correlation of Precambrian rocks in the British Isles. Harris, A L, and others (editors). Geological Society of London Special Report No. 6. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: