This account of the rocks of Unit 1 should be read with that for Key Site 1148 ‘Devonian - Red Arch Formation; Cushendall to Red Arch, Glenariff' which places them in context.
Unit 1 consists of a variety of red conglomerates, extending along 400m of coast southwards from Lifeboat House. Beds of pebbles, cobbles and boulders in direct contact with each other form traceable beds up to 1.5m thick. Towards the top of the unit and the unconformity with Unit 2, the conglomerates become finer and cross bedding carves them up into smaller units which have no lateral continuity.
These rocks were part of a fan of debris spilling out of an upland desert valley and banked against the lower slopes. The later, finer rocks were washed out into the lower desert basin by temporary streams flowing in branching channels.