This example at Derry in County Cork sits in rough grazing land, a kidney-shaped mound of burnt and fire-cracked stone measuring roughly 13.5 metres long, 15.8 metres wide, and half a metre high. A two-metre opening faces northwest, which is typical of the form: the hollow once held a trough, and the mound itself is the accumulated debris of thousands of heating episodes, stones discarded after they cracked from repeated immersion in water.

Fulachtaí fia, the term generally translated as something like "burnt mounds", date predominantly to the Bronze Age, though some examples span a wider period. The standard interpretation is that stones were heated in a fire, then dropped into a water-filled trough to bring it to the boil, the cracked and spent stones being raked to the side after each use. What exactly was being boiled remains genuinely debated: cooking meat is the traditional explanation, but experimental archaeology has also demonstrated the feasibility of brewing, hide-working, and bathing. The kidney or horseshoe shape is characteristic, the hollow of the curve marking where the trough once sat. This particular mound, modest in height but broad across its footprint, is a fairly representative example of the type.