The only evidence of its existence came from a plough: when the field was turned, a scatter of cracked stone and black soil came to the surface, the classic signature of a fulacht fia. These prehistoric cooking sites, found in enormous numbers across Ireland, typically consist of a trough that was filled with water and heated by dropping fire-cracked stones into it, with the shattered, heat-spent stones accumulating nearby into a mound. At Shanaknock, the mound itself, if one ever rose above the ground, is long gone, absorbed back into the earth through centuries of agriculture.

The site was possibly noted as early as 1934, when a researcher named Bowman recorded what may have been three fulachta fiadh on land belonging to a D. O'Riordan in the area, a cluster of sites on the same holding that suggests this part of North Cork saw repeated prehistoric activity. The connection between the Shanaknock site and Bowman's record is not certain, but the proximity and the consistent physical description make it plausible. Fulachta fiadh are generally dated to the Bronze Age, roughly 1500 to 500 BC, though some examples fall outside that range, and they remain one of the most common field monuments in the Irish countryside, even when, as here, there is nothing left to see.