But local people once had a name for it and for others like it in the area: ceárta brannach, roughly translatable as a kind of forge. When ploughs broke into these mounds, what came up looked uncannily like the burnt and blackened debris found around a blacksmith's fire. The association is understandable, if mistaken. What they were actually disturbing was something far older.

The monument at Tullagh is a fulacht fia, a type of prehistoric cooking site found in large numbers across Ireland, typically dating to the Bronze Age. The usual interpretation is that stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, used for cooking meat and possibly for other purposes including bathing or textile production. The process leaves behind quantities of fire-cracked, heat-shattered stone, dark and friable, which would indeed have puzzled anyone encountering it without context and might reasonably have suggested a place where metal had been worked. At Tullagh, the mound is horseshoe-shaped, a classic form for these sites, opening to the north-west, with maximum dimensions of around ten metres by nine metres and a height ranging from roughly thirty centimetres to eighty centimetres. The sunken area at its centre marks where the trough once sat, measuring about three metres by one and a half metres. The site sits at the bottom of a north-east-facing slope in rough pasture, with a stream running approximately five metres to the north, which would have supplied the water essential to the whole operation. MacMahon, recording the site in 1991, preserved that local tradition of the ceárta brannach, a reminder that communities were constructing explanations for these enigmatic lumps in the ground long before archaeology offered a more systematic account.