The BGS Lexicon of Named Rock Units — Result Details

Nant-Y-Bache Group [Obsolete Name And Code]

Computer Code: NBG Preferred Map Code: notEntered
Status Code: Index Level
Age range: Ludlow Epoch (SU) — Ludlow Epoch (SU)
Lithological Description: Fine grained uncleaved sandstones (often deformed) and roughly cleaved sandy shales.
Definition of Lower Boundary: Drawn at the base of the Nant-Y-Bache Group where it rests conformably on thin-bedded shales and mudstoness of the Glyn-Dyfrdwy Group.
Definition of Upper Boundary: Drawn at the conformable upward passage from its uncleaved sandstones and shales to thin-bedded flaggy shales with siltstones of the Vivod Group.
Thickness: 300 metres approx.
Geographical Limits: Llangollen, north Wales.
Parent Unit: Not Entered (?)
Previous Name(s): none recorded or not applicable
Alternative Name(s): Elwy Group
Stratotypes:
Type Area  Llangollen, Clwyd. 
Reference(s):
Wills, L J and Smith, B, 1922. The Lower Palaeozoic Rocks of the Llangollen district with special reference to Tectonics. Quarterly Journal of the Geological Society, Vol.78, p.176-226. 
Wedd, C B, Smith, B and Wills, L J. 1927. The geology of the country around Wrexham, Part 1. Lower Palaeozoic and Lower Carboniferous rocks. Memoir of the Geological Survey of Great Britain. [London: HMSO.] 179pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable