The BGS Lexicon of Named Rock Units — Result Details

Penmaen Dewi Shale Formation

Computer Code: PED Preferred Map Code: PeD
Status Code: Pending Upgrade
Age range: Arenig Series (OR) — Arenig Series (OR)
Lithological Description: Dark blue cleaved mudstones.
Definition of Lower Boundary: Not defined.
Definition of Upper Boundary: Not defined.
Thickness: c.300 metres.
Geographical Limits: 1:50,000 Sheet 209 (St.Davids) and adjacent areas.
Parent Unit: Not Applicable (-)
Previous Name(s): Tetragraptus Shales (-3608)
Road Uchaf Formation [Obsolete Code: Use UCHA] (-2360)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Hicks, H. 1874. On the Succession of the Ancient Rocks in the vicinity of St. Davids Pembrokeshire, with special reference to those of the Arenig and Llandeilo Groups and their fossil contents. Quarterly Journal of the Geological Society, Vol.31, p.167-195. 
Hughes, C P. 1982. "In" Bassett, M G. (Editor). Geological Excursions in Dyfed, South West Wales. Published for the Geologists' Association, South Wales Group by the National Museum of Wales, p.327. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E209 E210