Drumarg ASSI

The disused quarry and lands at Drumarg are of importance because of their geology and the presence of an associated cave system. In particular the former quarry exposes limestone forming part of the Armagh Group of Carboniferous age. The development of the cave system here is notable given that nearly all of Northern Ireland’s cave series are found in the Carboniferous limestones of Co. Fermanagh.

The 200m long outcrop is one of the finest exposures in the area displaying about 10m thickness of limestone, the youngest (uppermost) occurring at the north-west end of the site. The lowest beds represent about 2.25m of grey, medium to coarse grained limestone with units of calcareous shale. Above this are 4.4m of thickly bedded, fine grained limestone broken into angular fragments (breccias) generated during the formation of ancient soils (pedogenesis).

The cave passages host a sizeable population of the Cave Spider Meta menardi.