The BGS Lexicon of Named Rock Units — Result Details

Blackbyre Limestone

Computer Code: BBLS Preferred Map Code: notEntered
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: A pale to dark grey, crinoidal, bioclastic, argillaceous limestone interpreted to be of marine origin generally with a massive lower portion and a thinly bedded upper part, and is a name applied to limestone beds within the Balgrochan Beds., which are mostly mudstones.
Definition of Lower Boundary: Usually seen as a change from an apparently marine mudstone, known as the Balgrochan Beds, in the Lawmuir Formation.
Definition of Upper Boundary: Mostly identified by a change to probable marine mudstone of the Balgrochan Beds in the Lawmuir Formation overlain by non-marine strata locally including the freshwater Baldernock Limestone.
Thickness: Generally up to 0.35m thick, and possibly up to 7.0m in the Paisley and Glasgow districts. Elsewhere, the unit is represented by the Balgrochan Beds.
Geographical Limits: The Paisley and Glasgow area.
Parent Unit: Lawmuir Formation (LWM)
Previous Name(s): Nodular White Limestone [Obsolete Name and Code: Use BBLS] (-42)
Douglas Under Limestone [Obsolete Name And Code: Use BBLS] (DULS)
Stonehouse Under Limestone [Obsolete Name And Code: Use BBLS] (STUL)
Muirkirk Under Limestone [Obsolete Name And Code: Use BBLS] (MULS)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  The unit is 0.83 m thick, with the base measured at a depth of 16.93m in the Lawmuir Formation No. 1A borehole, BGS reg NS57SW/162, west of Bearsden near Glasgow. Blackbyre(s) is southeast of Paisley and north of Barrhead. 
Reference(s):
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). 
Hall, I H S, Browne, M A E and Forsyth, I H. 1998. Geology of the Glasgow district. Memoir of the British Geological Survey, Sheet 30E (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S023 S030 S030