Others exist only as a mark on a map, their physical presence long since absorbed back into the land. At An Tseanchluain in County Cork, a fulacht fia, one of Ireland's most common and most quietly mysterious monument types, sits somewhere beneath ordinary pasture with no visible surface trace remaining. A fulacht fia is essentially a prehistoric cooking or industrial site, typically identified by a horseshoe-shaped mound of burnt and fire-cracked stones, accumulated over repeated use. The method involved heating stones in a fire and dropping them into a water-filled trough to bring it to the boil. Thousands of these sites survive across Ireland, mostly Bronze Age in date, yet each individual example carries its own small puzzle of where exactly it lies and what, precisely, it was used for.

The site at An Tseanchluain is known from a map produced by the UCC Archaeology Department, which recorded it under the older spelling 'fulacht fiadh'. Beyond that notation, detail is sparse. There are no associated finds, no recorded excavation, and nothing visible at ground level to mark the spot. It appears in the Archaeological Inventory of County Cork, Volume 3, covering Mid Cork, published in 1997, which suggests it was recognised as a site of archaeological significance even in the absence of surface evidence. Ploughing, land improvement, or simply the slow settling of centuries can reduce a fulacht mound to an invisible spread of charcoal and heat-shattered stone beneath the topsoil, detectable only by geophysical survey or chance exposure. The place name An Tseanchluain, meaning something close to 'the old meadow' or 'the old pasture' in Irish, has a faintly recursive quality given that the site itself now lies invisible beneath exactly that kind of ground.