The BGS Lexicon of Named Rock Units — Result Details

Ballyshannon Limestone Formation

Computer Code: BAL Preferred Map Code: BAL
Status Code: Full
Age range: Chadian Substage (CI) — Arundian Substage (CJ)
Lithological Description: Limestone, dark blue-grey, bioclastic, argillaceous packstones, interbedded with dark grey, silty shale; rarely with chert nodules in upper part; named members include sandstones.
Definition of Lower Boundary: Lowest member of the formation, the Gortnaree Sandstone Member, conformably succeeds the Termon River Limestone Formation.
Definition of Upper Boundary: Highest member of the formation, the Ederny Limestone Member, is overlain disconformably by the normal Bundoran Shale Formation or the sandstone basal member in the Kesh-Omagh area and southwest County Fermanagh.
Thickness: 120 - 450 metres.
Geographical Limits: Northwest Carboniferous basin of Ireland.
Parent Unit: Tyrone Group (TYRO)
Previous Name(s): Lower Limestone (GLRB)
Pettigo Limestone Group [Obsolete Name And Code: Use BAL] (PELG)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The area around Ballyshannon, County Sligo. In a road cutting, 1.6 km east of the town and south of Knader Lough, basal dolomitic conglomeratic limestones rest unconformably on 'Moine' quartzites. Centred on 10km Grid Square C 18 36. 
Reference Section  Corn Quarry, 2.1 km south east of Ederny, County Fermanagh. This quarry and other abandoned sites on Corn Ridge expose completely the top 50 metres of the formation including some new members. 
Reference(s):
Simpson, I M, 1954. The Lower Carboniferous stratigraphy of the Omagh Syncline, Northern Ireland. Quarterly Journal of the Geological Society of London, Vol.110, 391-408. 
Oswald, D H, 1955. The Carboniferous rocks between the Ox Mountains and Donegal Bay. Quarterly Journal of the Geological Society of London, Vol.111, Part 2, 167-186. 
Brunton, C H C and Mason, T R, 1979. Palaeoenvironments and correlation of the Carboniferous rocks in west Fermanagh, Northern Ireland. Bulletin of the British Museum of Natural History (Geology), Vol.32, 91-108. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
N32