It measures roughly twelve metres north to south and six metres east to west, and beneath its turf covering lies a heap of burnt, heat-shattered stone, the accumulated residue of prehistoric cooking. This is a fulacht fia, a type of ancient outdoor cooking site found in great numbers across Ireland, typically consisting of a trough filled with water, a nearby hearth for heating stones, and a mound of the cracked and discarded stones that built up over repeated use. The proximity to the spring here is no accident; a reliable water source was the whole point.

Fulachta fiadh are most commonly dated to the Bronze Age, roughly 2000 to 500 BC, though some examples span a wider range. The working method, as archaeologists have reconstructed it, involved heating stones in a fire until they were extremely hot, then dropping them into a water-filled trough to bring the water rapidly to the boil. Meat could then be cooked in the heated water. Over time, the used stones, which fracture and crumble under thermal shock, were raked aside and discarded, forming the characteristic horseshoe-shaped or oval mound that survives today. The Downing example is not an isolated find; it belongs to a cluster of four such sites in the immediate area, suggesting repeated, perhaps seasonal, activity at this particular spot over a long period.