It is, in fact, the accumulated debris of prehistoric cooking, a fulacht fia, the term used for the fire-cracked stone mounds that are among the most common ancient monuments in Ireland. The basic method involved heating stones in a fire, dropping them into a water-filled trough until the water boiled, and repeating the process until whatever was being cooked was done. Over time, the shattered, heat-spent stones were piled to one side, building up the distinctive mounds that survive across the Irish landscape thousands of years later.

This particular example measures roughly six metres east to west and just under six metres north to south, rising to about three-quarters of a metre in height. Its shape is kidney-like, with a slight indentation along its western side, and burnt material is visible at the surface near the southern stream, where erosion or past disturbance has broken through the grassy crust. The placement here is typical: fulachta fia are almost invariably found close to water, which was both a practical necessity for the cooking process and likely a factor in choosing the site in the first place. The two streams that flank the mound to the north and south flow north-westward from the slopes of Knockeirky, and a small boulder sits at the northern tip of the mound, close to the nearer stream. Some twenty-five metres to the north-east lies a separate enclosure, a reminder that ancient sites in Kerry rarely exist in true isolation; the landscape around them tends to reward a slow, wide-eyed look rather than attention fixed on a single feature.