There is nothing above ground to mark it out; to the casual eye it is simply soil. What it represents, however, is the footprint of a fulacht fia, one of the most common yet persistently enigmatic monument types in the Irish landscape.

A fulacht fia, sometimes called a burnt mound, is the debris left behind by a prehistoric cooking or heating site. The typical arrangement involved a trough, often timber-lined or cut into the earth, into which water was poured, and then heated by dropping fire-cracked stones into it. Those stones, once shattered by repeated heating and cooling, were discarded into a mound nearby. Over centuries, these mounds of blackened, fragmented stone accumulated into the low spreads that archaeologists now identify across Ireland in their thousands, concentrated particularly in low-lying, wet ground close to water sources. The presence of a field drain here is consistent with that pattern; these sites tend to cluster where water was reliably available. Bronze Age dates are most commonly associated with fulachtaí fia, though some span a wider range. The Rathonoane example, recorded in the Archaeological Inventory of County Cork, gives no specific date, only the physical reality of that burnt spread still lying in the ground beneath whatever crop the field happens to be carrying.