Its opening, five metres across, faces northeast. To a passing eye it might resemble little more than a low, overgrown earthwork, but the material it is made of tells a different story.

This is a fulacht fia, a type of prehistoric cooking or processing site found in very large numbers across Ireland, with particular concentrations in Munster. The term is an old Irish one, loosely meaning "cooking pit of the deer" or "cooking place of the wild animal", though the sites were used for far more than game cookery. The typical arrangement involved a trough, usually timber-lined or stone-lined, dug near a water source, filled with water, and then heated by dropping fire-cracked stones into it. Those stones, once used and discarded, accumulated over time into the characteristic horseshoe-shaped mound that defines these sites, with the open end facing the trough and water supply. The proximity of the Cork example to a natural spring fits this pattern precisely: a reliable water source was essential, and the northeast-facing opening would have kept the working area oriented towards it. Most fulachta fia date to the Bronze Age, broadly between 1800 and 800 BC, though some are earlier or later. The sheer scale of the mound here, nearly a metre and a half high after millennia of settling, suggests sustained and repeated use over a long period.