The BGS Lexicon of Named Rock Units — Result Details

Derryloran Formation

Computer Code: DLN Preferred Map Code: DLN
Status Code: Full
Age range: Visean Stage (CV) — Visean Stage (CV)
Lithological Description: Conglomerate, grit, sandstone and minor sandy dolomitic limestone.
Definition of Lower Boundary: Unconformable on pre-Carboniferous basement.
Definition of Upper Boundary: None
Thickness: 140-200m
Geographical Limits: South-east Tyrone, Northern Ireland.
Parent Unit: Armagh Group (ARMA)
Previous Name(s): Derryloran Grit Formation (Obsolete Name And Code: Use DLN) (-866)
Derryloran Grit Member (-213)
Derryloran Grit Formation [Obsolete Name And Code: Use DLN] (DLG)
Derryloran Grits (-1505)
Upper Calciferous Sandstone (-1506)
Replaced By Derryloran Formation (*772)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Ballinderry River, west of Cookstown. Kildress - Derryloran Bridge Drum Road - Bridge (Killymoon). 
Reference(s):
Geological Survey of Northern Ireland, 1983. Cookstown sheet 27, solid 1:50,000. 
Eagan, F W, 1881. Explanatory memoir to accompany sheet 27 of the maps of the Geological Survey of Ireland 
Fowler, A and Robbie, J A, 1961. The geology of the country around Dungannon. Memoir of the Geological Survey of Northern Ireland. 
Geological Survey of Northern Ireland 1979. Pomeroy, sheet 34, solid, 1:50 000. [Southampton, Ordnance Survey for Institute of Geological Sciences.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
N27 N34 N35