It measures roughly twelve metres across and rises only half a metre from the surrounding earth, modest dimensions that give little away. Yet that slight rise, and the five-metre depression at its centre, are the fingerprints of a fulacht fia, one of the most common and least understood monument types in the Irish archaeological record.

A fulacht fia is, in essence, the remains of an ancient cooking site, though the term covers a good deal of scholarly debate about function. The typical arrangement involves a trough dug into the ground, often timber-lined, which would be filled with water. Stones were heated in a nearby fire and then dropped into the trough to bring the water to a boil. Over time, the fire-cracked and shattered stones were raked out and piled to the side, gradually forming the low horseshoe-shaped or circular mound that survives today. The depression visible at the Farnanes site likely marks where that trough once sat. These monuments are found in their hundreds across Cork alone, and they tend to cluster in exactly the kind of wet, low-lying ground seen here, where water would have collected naturally or a trough could be kept reliably filled. Most date to the Bronze Age, broadly spanning from around 2000 to 500 BC, though some sites have produced dates outside that range.