A fulacht fia, the most common type of prehistoric monument found across Ireland, is essentially the debris left behind by repeated cycles of heating stones in fire and dropping them into a water-filled trough to bring it to the boil, a method of cooking that was practised here, as elsewhere, during the Bronze Age. What sets this particular example apart is the way it uses its setting so completely: the C-shaped mound, roughly 17 metres across east to west, wraps around a central hollow, and the rock face itself forms the southern wall, so that the trough is enclosed on three sides by the mound and on the fourth by bare stone. The arms of the mound meet the cliff directly, making the landscape an active part of the structure rather than just a backdrop.

The mound stands up to two metres high on its western side and is composed almost entirely of heat-shattered limestone fragments packed into a matrix of dark grey soil, the characteristic signature of a fulacht fia anywhere in Ireland. No standing water now sits within the trough hollow, though a spring issues from the base of the rock face about seven metres to the east, hinting at why this sheltered terrace was chosen in the first place. A cluster of similar sites in the immediate area was recorded by Tom Coffey in 1994, and the concentration is notable: a second fulacht fia sits just fifteen metres to the west on the same terrace, and two more lie on a lower terrace roughly 200 and 250 metres to the south-west. The grouping suggests sustained, repeated use of this corner of the Knockanes ridge rather than a single episode of activity.