This one in Knockane, County Cork, disappeared rather more abruptly, submerged beneath an artificial lake created by sand and gravel extraction works. What had once been recorded on the east side of a local stream, a fulacht fia, is now simply gone, along with at least two other examples of the same site type that stood nearby.

A fulacht fia, sometimes called a burnt mound, is one of the most common prehistoric monument types in Ireland. The term refers to a horseshoe-shaped mound of fire-cracked stones and charcoal-rich earth, typically found beside a water source. The accepted interpretation is that stones were heated in a fire and dropped into a water-filled trough, bringing the water rapidly to the boil; the cracked, discarded stones gradually built up into the characteristic mound. The Knockane example was noted on the Ordnance Survey six-inch map of 1938, which places it firmly in the documented record even if the physical evidence had already become difficult to read by the time fieldworkers came to assess it. When they did, there was nothing to find. The lake created by the extraction works had covered the site entirely, and the two neighbouring fulachta fiadh had met the same fate. Three related prehistoric monuments, clustered in the same stretch of ground beside a stream, all erased by the same industrial process.