The BGS Lexicon of Named Rock Units — Result Details

Topped Mountain Sandstone Formation

Computer Code: TPMS Preferred Map Code: TPMS
Status Code: Full
Age range: Asbian Substage (CR) — Brigantian Substage (CX)
Lithological Description: Sandstone, cross-laminated, grey, pink-purple stained, fine- to coarse-grained, subarkose with interbedded grey-red and green siltstones and mudstones; carbonate nodules.
Definition of Lower Boundary: Not seen; everywhere faulted.
Definition of Upper Boundary: First appearance of conglomerates and pebbly sandstones marks change to Ballyreagh Conglomerate Formation.
Thickness: At least 1000m
Geographical Limits: Southern sector of the Fintona Block, Northern Ireland.
Parent Unit: Kilskeery Group (KILS)
Previous Name(s): Shanmaghry Sandstone Formation (-1239)
Dingle Beds (-1993)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Summit of Topped Mountain and the spur trending northnortheast from the summit cairn, County Fermanagh, Northern Ireland. 
Reference(s):
Wilkinson, S B, 1882. The geology of the country around Eniskillen, Fivemiletown, Trillick, Lisbellew and Maguiresbridge. Explanatory Memoir to accompany Sheet 45 of the maps of the Geological Survey of Northern Ireland. Dublin and London. 
Mitchell, W I and Owens, B, 1990. The geology of the western part of the Fintona Block, Northern Ireland: Evolution of Carboniferous basins. Geological Magazine, Vol.127 (5), 407-426. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
N33 N45