The site is a fulacht fia, a type of monument found in considerable numbers across Ireland, consisting essentially of a horseshoe-shaped mound of fire-cracked stones accumulated beside a trough. The typical method involved heating stones in a fire and dropping them into a water-filled pit to bring it to the boil, a process that eventually left the stones spent and shattered, piled up around the trough over repeated use. What survives at Ballynatona is less visible than most: the buried spread of that burnt material, glimpsed only when the field happened to be ploughed.

The detail comes from local knowledge rather than formal excavation. A farmer or neighbour noticed the dark, heat-fractured spread of material turning up in the furrows, which is itself a fairly common way that fulachta fia come to light in agricultural land. The burnt mounds that characterise these sites are typically dateable to the Bronze Age, broadly speaking somewhere between 1500 and 500 BC, though many have never been excavated and their precise date and function remain open questions. Some researchers have argued for uses beyond cooking, including textile processing or bathing, though none of that has been tested at Ballynatona. For now it sits quietly under grass, its outline unknown, its full extent unexcavated.