They look, to an untrained eye, like nothing more than slight rises in a soggy field. Beneath the turf, however, each one is packed with burnt stone and blackened soil, the accumulated debris of a practice that was repeated across prehistoric Ireland with remarkable consistency.

These are burnt mounds, sometimes called fulacht fiadh in Irish, a type of site found in their thousands across the island and typically dated to the Bronze Age, though some span a wider range. The working theory, supported by experimental archaeology, is that they were used for cooking or heating water: stones would be heated in a fire, then dropped into a water-filled trough until the liquid boiled, and the cracked, spent stones discarded into a heap nearby. Over many episodes of use, those heaps grew into the low mounds we see today. The site at Clahane fits the pattern well. A small stream, a tributary of the River Lee, runs along the western boundary of the field, providing the reliable water supply these sites almost always require. At least five distinct mounds were identified here, with the possibility that a further dozen or so less well-defined mounds in the same field belong to the same tradition. One of the more modest examples measures seven metres north to south, six metres east to west, and just thirty centimetres in height, with no visible trough surviving at the surface. The survey of the Lee Valley area in which these sites were recorded was carried out in 1996 and 1997.