The BGS Lexicon of Named Rock Units — Result Details

Dromore Sandstone Member

Computer Code: DOSM Preferred Map Code: DOSM
Status Code: Full
Age range: Arundian Substage (CJ) — Arundian Substage (CJ)
Lithological Description: Sandstone, white-fawn, medium to coarse-grained, micaceous; calcareous horizons, weathering orange-brown, are friable and sparsely fossiliferous, bioturbated, cross-bedded, sporadic beds of crinoidal, sandy packstone.
Definition of Lower Boundary: Conformable; abrupt change from interbedded blocky mudstones, micaceous and blocky siltstones and blue-grey silty sandstones, at top of Bundoran Shale Formation, to orange weathering, thick beds of medium-grained sandstone.
Definition of Upper Boundary: Abrupt change, probably disconformable, between sandstones and overlying part of Mullaghmore Sandstone Formation, predominantly grey calcareous mudstones and thin peritidal limestones.
Thickness: c.20 - 25m
Geographical Limits: Kesh-Omagh area of the northwest Carboniferous basin of Ireland.
Parent Unit: Mullaghmore Sandstone Formation (MMS)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Partial Type Section  South-flowing stream on east side of Glenvannan Townland, 10m upstream of road culvert. Exposes top of the member and succeeding strata. 
Partial Type Section  Deeply incised White Glen, 1.77km west-north-west of Dunnaree Hill, c.80m north of road bridge. Exposes base of the member and underlying strata. 
Type Section  Disused quarry in Drumore Big Townland. Exposes c.10m of sandstones just below top of member. Long southerly inclined dip slope, south of quarry, is top sandstone bed. 
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. 
Mitchell, W I, Johnston, T P and Legg, I C. 2004. Geology of the country around Kesh, Co. Fermanagh and Omagh, Co. Tyrone. Geological Sheets 32 and part of 31 (Kesh) and 33 (Omagh). Geological Survey of Northern Ireland. Technical Report GSNI 04/1. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: