The BGS Lexicon of Named Rock Units — Result Details

Upper Caithness Flagstone Subgroup

Computer Code: UCF Preferred Map Code: UCF
Status Code: Pending Upgrade
Age range: Givetian Age (DV) — Givetian Age (DV)
Lithological Description: Laminated carbonate rich siltstones and shales with subordinate fine-grained, thinly bedded sandstones.
Definition of Lower Boundary: Drawn at the base of the Achanarras Formation, where limestone rests conformably upon sandstone and shale of the Robbery Head Formation.
Definition of Upper Boundary: Drawn at the conformable upward passage of lacustrine sandstone of the Mey Flagstone Formation to fluvial sandstone of the John O'Groats Sandstone Group.
Thickness: c.1500m
Geographical Limits: Northern Highlands of Scotland.
Parent Unit: Caithness Flagstone Group (CNFL)
Previous Name(s): Thurso Group (-2513)
Upper Caithness Flagstone Formation (-584)
Caithness Flagstone Series (-4751)
Upper Caithness Flagstone Group (-4380)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The County of Caithness. 
Reference(s):
Carruthers, R G, 1909. On the stratigraphic position of the Achanarras fauna in the Old Red Sandstone of Caithness. Summary of Progress of the Geological Survey of Great Britain for 1908. 
Phemister, J. 1948. British Regional Geology: Scotland: the Northern Highlands (2nd edition) (Edinburgh: HSMO for the Geological Survey and Museum.) 
Crampton, C B and Carruthers, R G, 1914. The geology of Caithness. Memoir of the Geological Survey, Scotland. Sheets 110 and 116 (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S115