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)
Caithness Flagstone Series (-4751)
Upper Caithness Flagstone Group (-4380)
Upper Caithness Flagstone Formation (-584)
Alternative Name(s): none recorded or not applicable
Type Area  The County of Caithness. 
Phemister, J. 1948. British Regional Geology: Scotland: the Northern Highlands (2nd edition) (Edinburgh: HSMO for the Geological Survey and Museum.) 
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. 
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: