When a stream channel on Clare Island was widened and deepened, the newly cut eastern bank revealed a thin, intermittent layer of heat-fractured stones and charcoal, measuring roughly 2.7 metres in length and only 0.15 metres thick. It is an easy thing to miss, especially buried 0.3 to 0.5 metres below the surrounding ground surface, and yet it represents one of the most common prehistoric monument types in Ireland. A fulacht fia, pronounced roughly "foolacht fee-ah", is a burnt mound, the residue of repeated cycles of heating stones in fire and then dropping them into a water-filled trough to bring it rapidly to the boil. Thousands survive across the island of Ireland, typically dating to the Bronze Age, and their purposes have been debated for decades, with cooking, brewing, and textile processing among the more plausible suggestions.

This example sits in enclosed farmland at the foot of the steep southern slopes of the wide valley lying to the west of the island's harbour, below the West Road and just north of the island's old generating station. The deposit lies precisely at the break of slope, where the hillside levels out onto what was once a flat, marshy valley floor, now reclaimed. That location is characteristic; fulachta fiadh are almost always found near water and in low-lying, naturally wet ground. Here the stream, recently redirected, bends from a diagonal course down the hillside into a north-south channel running parallel to an earthen field boundary, and it is in the cut face of that channel that the monument is exposed. Charcoal dominates the deposit, with heat-shattered stone and one or two fragments of white quartz mixed through it. Beneath the burnt layer lies around 0.3 metres of peat, which in turn rests on the gravelly subsoil of the stream bed. No corresponding layer is visible in the western bank, though that bank is considerably degraded.

The find was documented as part of the New Survey of Clare Island, a substantial archaeological project whose fifth volume, edited by Paul Gosling, Conleth Manning, and John Waddell, was published by the Royal Irish Academy in 2007. Clare Island, lying at the mouth of Clew Bay in County Mayo, has long attracted archaeological attention, and this modest smear of charcoal and burnt stone in a freshly cut drainage ditch quietly extends that prehistoric record into the island's lower, wetter margins.