When the field is ploughed, burnt material rises to the surface, a quiet signal that something far older lies just below the topsoil.

The site is a fulacht fia, a type of monument found in great numbers across Ireland, typically dating to the Bronze Age. The basic form involves a trough, often timber-lined or stone-lined, filled with water and heated by dropping fire-cracked stones into it. Those stones, once used and shattered by thermal shock, were discarded into a mound nearby, and it is precisely this mound of dark, heat-fractured material that tends to survive. At Derrynagasha, the land has long since been brought into agricultural use, and the original mound is no longer visible as a surface feature. What remains is the memory of the site, preserved in local knowledge and confirmed each time a plough cuts deep enough to disturb the buried burnt stone.

The detail that local people knew what the dark soil meant, and passed that information along, is itself worth noting. Many fulachtaí fia survive precisely because farming communities recognised the significance of the discolouration and unusual stone scatters that turned up in their fields, even without a formal name for what they were looking at.