The BGS Lexicon of Named Rock Units — Result Details

Hurlet Coal

Computer Code: HURC Preferred Map Code: notEntered
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: A bright banded coal, containing vitrinite with some inertinite (including fusinite = mineral charcoal); commonly recorded as pyritous and dirty but with good coking properties.
Definition of Lower Boundary: Generally identified by a grey, rooted seatearth or seatclay just above the non-marine Baldernock Limestone, almost at the top of the Lawmuir Formation in the Glasgow area, or almost at the top of the West Lothian Oil-shale Formation in West Lothian (no Baldernock Limestone). Considered as a conformable contact and defined as the lithological change from the underlying strata.
Definition of Upper Boundary: Usually seen as a change to mudstone, locally Lingula-bearing or marine, underlying the Hurlet Limestone, that forms the base of the Lower Limestone Formation. Noteworthy, is the presence in some areas (eg Lennoxtown northeast of Glasgow) of the marine Alum Shale bed (1-2m thick) in this interval. Considered as a conformable contact and defined as the lithological change to the overlying strata.
Thickness: Varies from a few centimetres, to 2.4m (south of Blackburn in West Lothian) to 1.32m in the Milngavie No.1 Borehole [BGS Registered No.NS57SE/39, NGR NS 5501 7335] in the Glasgow district. Known to be 1.6m thick in the Bathgate area of West Lothian, encountered at a depth of 152.3m in Murrayfield No.1 Borehole, BGS Registered No.NS96NE/276, NGR NS 9875 6554.
Geographical Limits: Present throughout the outcrop of the Lawmuir Formation in the Glasgow-Paisley area of the Carboniferous of the Midland Valley of Scotland, but absent on highs largely created by the Clyde Plateau Volcanic Formation; also developed in West Lothian in the West Lothian Oil-shale Formation of the Bathgate area.
Parent Unit: Lawmuir Formation (LWM)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Hurlet [NS 515 609] along with Nitshill [NS 521 604] is the type area for this seam in the southwest of Glasgow. Hinxman et al., 1920. 
Reference Section  Measured as 0.49m thick with base at a depth of 299.54m in the Wester Gartshore Colliery Underground Borehole, BGS Reg. No.NS 67 SE/99 at Kirkintilloch northwest of Airdrie. 
Reference(s):
Hinxman, L W, Anderson, E M and Carruthers, R G. 1920. The economic geology of the Central Coalfield of Scotland, Area IV; Paisley, Barrhead, Renfrew. Memoir of the Geological Survey, Scotland. 
Cameron, I B, Aitken, A M, Browne, M A E and Stephenson, D. 1998. Geology of Falkirk District. Memoir of the British Geological Survey Sheet 31E (Scotland). 
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Aidrie 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:
S031 S031 S024 S030 S030