The BGS Lexicon of Named Rock Units — Result Details

Dounans Limestone Formation

Computer Code: DSLM Preferred Map Code: notEntered
Status Code: Full
Age range: Arenig Series (OR) — Arenig Series (OR)
Lithological Description: Limestone, massive, grey, fractured and veined; dolomitised and silicified over much of outcrop. Locally fossiliferous with a trilobite - brachiopod - gastropod faunal assemblage.
Definition of Lower Boundary: Limestone is unconformable on largely carbonated and silicafied Lime Hill Serpentinite.
Definition of Upper Boundary: Not seen; unit has faulted and/or unconformable relationship with overlying Old Red Sandstone conglomerates and sandstones.
Thickness: c.20m (estimated).
Geographical Limits: Ground around Lime Craig Quarry, Aberfoyle, but possible correlations in the Highland Border Complex are known at several localities adjacent to the Highland Boundary in Scotland; eg Margie Limestone, North Esk.
Parent Unit: Highland Border Complex (HBX)
Previous Name(s): Dounans Limestone (-4625)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Lime Craig Quarry, 1.5km north-ast of Aberfoyle, Perthshire. 
Reference(s):
Ingham, J K, Curry, G B and Williams, A, 1985. Early Ordovician Dounans Limestone fauna, Highland Border Complex, Scotland, Transactions of the Royal Society of Edinburgh; Earth Sciences, Vol.76, 481-513. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S038