The BGS Lexicon of Named Rock Units — Result Details

Polglaze Formation

Computer Code: POLG Preferred Map Code: Polg
Status Code: Full
Age range: Early Devonian Epoch (DL) — Early Devonian Epoch (DL)
Lithological Description: A dark grey, slatey cleaved mudstone, which has a marked absence of coarser lithologies, and showing low grade (anchizone) regional metamorphism.
Definition of Lower Boundary: Faulted against the Portscatho Formation, comprising predominantly turbiditic sandstone beds.
Definition of Upper Boundary: Faulted against the Hallane Formation, seen as a mudstone with siltstone and limestone.
Thickness: Unknown, as obscured by complex folding, but probably at least 500m.
Geographical Limits: Mevagissey Sheet 353 (England and Wales), but is known to extend northwards onto the Bodmin and St. Austell Sheet (347), for which no modern mapping is available.
Parent Unit: Meadfoot Group (MDT)
Previous Name(s): MEADFOOT BEDS (MDT)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Coastal section between Polrudden Cove and Polgwyn Beach. 
Reference(s):
Reid, C. 1907. Geology of the country around Mevagissey. Memoir of the Geological Survey of Great Britain. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E353 E354