On a gentle east-facing slope in Mountbolton, Co. Waterford, a patch of shattered and fire-blackened stone sits largely unnoticed, its significance easy to miss for anyone who does not know what they are looking at. It measures roughly two metres by one and a half, which is to say it is about the size of a large dining table, yet what it represents is a technology thousands of years old and once widespread across the Irish landscape.

A burnt mound is, at its simplest, the debris of repeated heating. Stones were placed in fire, then plunged into water-filled pits or troughs to raise the temperature rapidly, a method used in prehistoric times for cooking, bathing, or industrial processes such as working hides. The stones crack and shatter under thermal stress, becoming useless for further heating, and are then discarded in a mound nearby. Over centuries, these accumulations of broken, heat-reddened stone become a quiet but legible record of sustained human activity. The Mountbolton example came to light in 1986, when a Bord Gáis pipeline was being laid through the area. Fieldnotes recorded at the time by M. Gowen documented the small concentration of burnt and broken stone, preserving at least a trace description of something that might otherwise have been churned into oblivion without remark.