The BGS Lexicon of Named Rock Units — Result Details

Pontesford Shales Formation

Computer Code: POSH Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Harnagian Substage (OG) — Soudleyan Substage (OY)
Lithological Description: Black pyritous mudstones overlie a basal conglomerate and are succeeded by buff weathering, greenish grey, silty micaceous mudstones and siltstones.
Definition of Lower Boundary: Basal conglomerate overlies Uriconian Group (Precambrian) volcanic rocks with marked unconformity.
Definition of Upper Boundary: Not seen.
Thickness: At least 50m
Geographical Limits: Not recorded.
Parent Unit: Not Applicable (-)
Previous Name(s): Pontesford Shales (-4848)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Dean, W T and Dineley, D L, 1961. The Ordovician and associated Pre-Cambrian rocks of the Pontesford District, Shropshire. Geological Magazine, Vol.98, 367-376. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable