To place this site in context, the Slieve Gullion Ring – Overview, site 1118, should be read.
The prominent, crag-lined gully running north from a bend in the road, cuts completely through the ring dyke, exposing both the inner and outer contacts of the porphyritic granophyre with Newry granodiorite host rock. Contacts within the granophyre show that it underwent many pulses of intrusion and near its centre, large, alien blocks of well rounded, fine-grained granitic rock up to a metre across can identified. The origin of these blocks has been much debated, some geologists believing them to be altered Newry granodiorite.
At the head of the gully where the outer contact is seen there is a zone of intensive crushing affecting both the granophyre and the Newry granodiorite of the ring wall.
This is one of suite of sites selected to illustrate the nature of the Slieve Gullion Ring complex. All are of international importance and should be scheduled and managed to preserve their interest.