There are at least five of them, clearly defined, and possibly as many as seventeen if the less obvious humps scattered across the same field are counted. Each contains burnt stone and blackened soil, the characteristic debris of prehistoric cooking activity. A small stream, a tributary of the River Lee, runs along the western edge of the field, and that proximity to water is no accident.

These are fulachtaí fia, a type of Bronze Age cooking site found in enormous numbers across Ireland, typically in low-lying, wet ground near a water source. The standard interpretation is that a wooden trough was sunk into the earth and filled with water, which was then heated by dropping fire-heated stones into it until it reached boiling point. The discarded stones, cracked and blackened from repeated heating and cooling, accumulated into the horseshoe-shaped mounds that survive today. The best-preserved example at Clahane fits this form closely: it measures roughly 9.5 metres north to south and 11 metres east to west, and rises half a metre above the surrounding ground. At its centre, a trough area three metres square opens to the south and sits 0.30 metres below the crest of the mound. The site was recorded by Michael Connolly during a survey of the Lee Valley area carried out in 1996 and 1997, at which point only the five most clearly defined mounds were formally noted, leaving the status of the remaining dozen or so unresolved.

The setting itself adds a quiet strangeness to the place. That so many of these sites should congregate in a single marshy field, chosen and returned to over what may have been centuries of use, suggests this was not a casual or incidental location. The wet ground that makes the field awkward today was likely part of what made it useful then.