They look, at first glance, like nothing at all: low, dark spreads of cracked stone mixed into the soil, easily mistaken for field clearance or the aftermath of some agricultural accident. The example at Ballyvolane in County Cork is typical of the type in its modest appearance, an oval spread roughly 22 metres north to south and 16 metres east to west, sitting on a natural rise along a south-facing slope, its soil darkened by charcoal and littered with heat-shattered stone.

Burnt mounds, known in Irish archaeology as fulachtaí fia, are generally interpreted as the debris left by repeated cycles of heating stones in a fire and plunging them into a water-filled trough, most likely for cooking, though bathing, textile processing, and brewing have all been proposed. The stones crack and fragment under thermal stress and are eventually discarded in a spreading heap beside the trough. The Ballyvolane mound fits this picture closely. About 26 metres to the north of the mound's centre, a waterlogged area beside a field boundary may point to the original water source, possibly a spring well, which would have been essential to the whole process. A second possible burnt mound lies approximately 160 metres to the south-west, a reminder that these sites often cluster, perhaps because a reliable water source drew repeated activity to the same general area across generations.