The BGS Lexicon of Named Rock Units — Result Details

Dun Limestone Member

Computer Code: DNL Preferred Map Code: DNL
Status Code: Full
Age range: Asbian Substage (CR) — Asbian Substage (CR)
Lithological Description: A dark grey, argillaceous, crinoidal, shelly limestone with algal nodules, interpreted as being of marine origin, weathering to a rusty ochreous colour.
Definition of Lower Boundary: Generally a conformable change from a thin marine mudstone overlying a thin coal or seatearth.
Definition of Upper Boundary: Generally a conformable change to marine mudstone, which in turn passes up into deltaic arenaceous deposits of the Tyne Limestone Formation.
Thickness: From 1.2m to 1.6m in the Eyemouth and north Berwickshire districts.
Geographical Limits: Confined to Berwickshire and north Northumberland in the Tyne Limestone Formation (TYLS) of the Yoredale Group (YORE). The contained marine fauna is equivalent to that of the MacGregor Marine Bands of the Midland Valley of Scotland.
Parent Unit: Tyne Limestone Formation (TYLS)
Previous Name(s): Lamberton Limestone [Obsolete Name And Code: Use DNL] (LALS)
Ladies Wood Limestone [Obsolete Name And Code: See DNL] (LDW)
Dun Limestone [Obsolete Code: Use DNL] (DUN)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Identified in the Marshall Meadows Borehole, BGS Reg. No.NT95NE/5, as a single leaf 1.57m thick with its base at 54.25m depth. 
Type Area  North side of Huds Head, Spittal, near Berwick on Tweed, Northumberland. Scrutton (1995). 
Reference(s):
Scrutton, C. 1995. Northumbrian rocks and landscape; a field guide. Yorkshire Geological Society, pp47-49. 
Tait, G. 1867. Miscellanea Geologica. Proceedings of the Berwickshire Natural History Club, V, 283-289. 
Greig, D C. 1988. Geology of the Eyemouth district. Memoir of the British Geological Survey, Sheet 34 (Scotland). 
Day, J B W and others, 1970. Geology of the neighbourhood around Bewcastle. Memoir of the British Geological Survey, Sheet 12. (England and Wales). 
Carruthers, R G, Burnett, G A and Anderson, W. 1932. The geology of the Cheviot Hills. Memoir of the Geological Survey of Great Britain, Sheets 3 and 5 (England and Wales). 
Frost, D V and Holliday, D W. 1980. Geology of the country around Bellingham. Memoir of the British Geological Survey, Sheet 13 (England & Wales). 
Gunn, W. 1900. The geology of the Belford, Holy Island and the Farne Islands, Northumberland. Memoir of the Geological Survey of Great Britain, Sheet 4 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E003 E004 E006 E001 E002 E034 E008 E009 E013