It is, in fact, a fulacht fia, a type of ancient cooking or processing site found in great numbers across Ireland, typically dating to the Bronze Age. The horseshoe or crescent shape is characteristic: the mound is the accumulated debris of burnt and shattered stone, built up over repeated use around a central trough where water was heated by dropping fire-cracked rocks into it. This particular example measures around thirteen metres in diameter and rises to a modest half metre at its highest point.

What gives the Carrig Island site an added layer of interest is its immediate setting. It lies close to a canal, with the land falling gently away in that direction, and just across that waterway stands a second fulacht fia. Water was essential to how these sites functioned, so proximity to a reliable source was no accident. Finding two such monuments within a field of each other, separated only by a canal, suggests this stretch of north Kerry was visited or settled repeatedly, its landscape shaped by the same practical logic generation after generation. The sites were recorded as part of the North Kerry Archaeological Survey, compiled by C. Toal and published in 1995, which documented the broader pattern of prehistoric activity across this corner of the county.