The term refers to a burnt mound, typically the accumulated debris of repeated outdoor cooking or heating activity, where stones were fired in a hearth and then dropped into a water-filled trough to bring it to the boil. Thousands survive across the island, often as low, horseshoe-shaped humps in damp ground, and the majority date to the Bronze Age. The example in Derrigra By., County Cork, would likely have remained anonymous field archaeology had a gas pipeline not cut directly through the area.

The site came to light in 2000 during topsoil stripping carried out ahead of the laying of the Ballincollig to Ballineen gas pipeline. By that point it had already been considerably reduced, having been levelled at some earlier stage during local land drainage works, and the stripping caused further damage. What excavation did recover was a spread of heat-shattered stones and charcoal-enriched soil measuring roughly seven metres east to west and just under five metres north to south, sitting in a stream valley within pasture land. Beneath that spread, archaeologists identified a possible trough, approximately 1.62 metres by 1.47 metres, whose lining offered an unexpectedly fine detail: wicker and wattle woven together and pressed into an impermeable clay to hold water. That combination of organic lining set in puddled clay is a practical and elegant solution to the problem of keeping a pit watertight, and finding it preserved well enough to identify the wattlework gives the site a specificity that its battered condition might otherwise have obscured.