The BGS Lexicon of Named Rock Units — Result Details

Hallane Formation

Computer Code: HALL Preferred Map Code: Hln
Status Code: Full
Age range: Early Devonian Epoch (DL) — Early Devonian Epoch (DL)
Lithological Description: A dark grey slaty mudstone, with black mudstone nodules, sporadic thin siltstone lenses and dispersed limestone lenses, crinoidal and shelly in part and with subordinate laminated mudstone and siltstone.
Definition of Lower Boundary: Faulted - thought to be part of the Parautochtonous succession.
Definition of Upper Boundary: Faulted.
Thickness: Unknown: details obscure due to complex folding; possibly several hundred metres.
Geographical Limits: BGS 1:50 000 scale Sheet 353 (Mevagissey), (England and Wales).
Parent Unit: Meadfoot Group (MDT)
Previous Name(s): Meadfoot Beds (-76)
Alternative Name(s): none recorded or not applicable
Partial Type Section  Coastal section between Polgwyn Beach and the Vans. 
Reid, C, 1907. Geology of the country around Mevagissey. Memoir of the Geological Survey of Great Britain. (London: HMSO.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E353 E354