It contains burnt material, the compacted residue of an ancient cooking method, and it is barely perceptible against the surrounding pasture. It is a fulacht fia, the Irish term for a type of prehistoric cooking site found in enormous numbers across Ireland and Britain, typically Bronze Age in origin. The usual interpretation is that stones were heated in a fire, dropped into a water-filled trough to bring it to the boil, and used to cook meat. The troughs, once abandoned, filled with the discarded burnt and shattered stone, forming the low, often horseshoe-shaped mounds that survive today.

What gives this particular example a little more texture is that it appears not to have been alone. In 1934, a researcher named Bowman noted three fulachta fiadh in this general area, all on land belonging to a B. Purdon, and this mound at Coolbane is thought to be one of the group. The other two were recorded separately. Whether all three were in use at the same time, or represent different episodes of activity across generations, is not something the surface evidence can answer. What the clustering does suggest is that this stretch of streamside land was returned to repeatedly, which is a pattern seen elsewhere with fulachta fiadh; proximity to a reliable water source seems to have mattered far more than any other consideration in choosing where to establish them.