What shows in the exposed earth is a layer of burnt and fire-cracked stone, the signature material of a fulacht fia, one of the most common yet still somewhat mysterious monument types in the Irish prehistoric landscape. These sites, typically Bronze Age in date, are thought to represent outdoor cooking or food-processing places, where water was heated by dropping fire-heated stones into a trough. The shattered, blackened stone that results from this repeated thermal shock accumulates over time into a distinctive spread, often horseshoe-shaped in plan, that can survive in the ground for over three thousand years.

The site at Ballynaneening sits in pasture at the base of a glen, and it is the natural erosion of the stream bank that has brought the deposit to light. A researcher from University College Cork, Alan Hawkes, documented what the cutting action of the water had exposed. On the south-facing side of the bank, burnt material runs to a maximum length of 7.5 metres and reaches a thickness of 0.3 metres. The north-facing section, partially obscured by a more recent collapse of the bank, shows a length of around 10 metres and a thickness of 0.4 metres. These are not dramatic dimensions by any measure, but they are enough to outline a substantial deposit, one that would once have formed a low mound in the landscape before the ground swallowed it.