That is, in a sense, the whole point. Somewhere beneath a field in mid Cork lies a fulacht fia, one of thousands of ancient cooking sites scattered across the Irish countryside, and the only reason anyone recorded its existence at all is that a trackway was being cut to a new house when the ground gave up its secret. Once the work was done, the surface closed over again, leaving no visible trace.

A fulacht fia, sometimes called a burnt mound, is typically a horseshoe-shaped mound of fire-cracked stones and charcoal-rich soil, the accumulated debris of repeated episodes of heating stones and dropping them into a water-filled trough to boil or steam food. They are among the most common prehistoric monument types in Ireland, dating mostly to the Bronze Age, though their exact social function is still debated. Some archaeologists have proposed uses ranging from textile processing to bathing. The Coolyduff example was noted by Hartnett in 1939, the reference appearing in the published archaeological inventory of mid Cork. The circumstances of its discovery, a construction crew cutting a new access road, are entirely ordinary, which is part of what makes the record interesting. It was found not through any deliberate investigation but by accident, catalogued, and then effectively lost to view again.