The BGS Lexicon of Named Rock Units — Result Details

Downie's Loup Sandstone Formation [Obsolete Name: Use CYD]

Computer Code: DWS Preferred Map Code: notEntered
Status Code: Index Level
Age range: Visean Stage (CV) — Visean Stage (CV)
Lithological Description: Dominantly of white sandstone with subordinate pebbly sandstone and conglomerate containing abundant pebbles of limestone, quartz and mudstone. There are also some highly calcareous sandy beds (Francis et al., 1970). Sandstones within the unit are characterised by large scale cross-stratification (Read and Johnson, 1967). Toward the top of the formation increasing amounts of volcanic detritus appear (Francis et al., 1970).
Definition of Lower Boundary: There is passage by alternation with strata of the underlying Ballagan Formation, although locally the base is abrupt and possibly disconformable with erosion confined to local channels. The base of the unit is generally drawn at the lowest bed that is coarser than a fine-grained sandstone.
Definition of Upper Boundary: Lavas of the Clyde Plateau Volcanic Formation seem to rest without angular discordance on and define the upper boundary of the unit. In detail, the base of the lava pile is diachronous, as different flows seem to form the base of the volcanic succession at different localities.
Thickness: 108m (330 feet) at Stronend [NS 6300 8900], decreasing eastnortheastwards to 41.3m (126 feet) in the Stirling No.1 (Kaimes) Borehole [NS79SE/21] at NS7720 9454.
Geographical Limits: Around Fintry [NS 615 870] and Stirling [NS 800 930], Scotland.
Parent Unit: Inverclyde Group (INV)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Section  Downies Loup in the Gargunnock Burn. Francis et al., 1970. 
Francis, E H, Forsyth, I H, Read, W A and Armstrong, M. 1970. The geology of the Stirling district. Memoir of the Geological Survey of Great Britain, Sheet 39 (Scotland). 
Read, W A, and Johnson, S R H. 1967. The sedimentology of sandstone formations within the upper Old Red Sandstone and lowest Calciferous Sandstone Measures west of Stirling, Scotland. Scottish Journal of Geology, Vol.3, 242-267. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: