What the erosion exposed was unexpected in its detail: a wooden trough, partially intact, lined at its base first with bog myrtle leaves and then with moss, the gaps between the lower timbers packed with yet more moss to hold water. This is a fulacht fia, the term used for a type of prehistoric cooking or processing site found widely across Ireland, typically identified by a mound of fire-cracked stone beside a water source and the remains of a trough in which water was heated by dropping in stones from a fire.

When lake waters began undermining the western side of the mound in the early 1990s, a rescue excavation was carried out in 1992. The work, later reported by McDermott, revealed that the trough had been set into a depression cut through the underlying peat. The surviving eastern side and part of the northern side were constructed from roundwood timbers roughly six centimetres in diameter, laid horizontally one on top of the other and held in position with upright corner posts. The mound itself, measuring around 7.5 metres north-east to south-west and reaching a maximum height of just over half a metre, is composed of heat-shattered fragments of sandstone, conglomerate, and limestone, the accumulated debris of repeated heating and cooling. Charcoal retrieved from the site included ash, willow, alder, hazel, and birch, and radiocarbon dating of a timber sample placed the site firmly in the Bronze Age, returning a calibrated date of 1290 to 939 BC. Immediately to the west of the mound, an arc of upright stakes was found set into the lake bed; its relationship to the fulacht fia was unclear but considered a possible association. A second fulacht fia lies approximately 75 metres to the south-west along the same shore, suggesting this stretch of Lough More was a place people returned to, repeatedly, over a long stretch of prehistoric time.