The BGS Lexicon of Named Rock Units — Result Details

Bodwrog Member

Computer Code: BWG Preferred Map Code: Bwg
Status Code: Full
Age range: Longvillian Substage (OL) — Longvillian Substage (OL)
Lithological Description: Medium- to coarse-grained sandstones and subordinate mudstones.
Definition of Lower Boundary: Overlies, probably unconformably, the Allt Fawr Rhyolitic Tuff Formation, the base not being seen due to faulting.
Definition of Upper Boundary: Gradational, conformable transition into calcareous mudstones and subordinate sandstones of the Plastirion Member, (the latter is perhaps better considered as the undivided part of the Dwyfach Formation).
Thickness: 30m
Geographical Limits: Pwllheli and Nefyn districts, North Wales.
Parent Unit: Dwyfach Formation (DWF)
Previous Name(s): Penarwel Drive Beds (-99)
Llanbedrog Grits (-738)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Lower part of member exposed in quarry on hillside below Bodwrog Farm. Young et al., 2002. 
Partial Type Section  (Upper part) exposed in a small stream. 
Reference(s):
Fitch, F J, 1967. Ignimbrite volcanism in North Wales. Bulletin Volcanologique, 30, 199-219 
Young, T P, Gibbons, W and McCarroll, D. 2002. Geology of the country around Pwllheli. Memoir of the British Geological Survey, Sheet 134 (England and Wales). 
Matley, C A, 1938. The geology of the country around Pwllheli, Llanbedrog and Madryn, southwest Carnarvonshire. Quarterly Journal of the Geological Society of London, Vol.94, 555-606. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable