At Lissard in County Cork, a mound of roughly ten metres in diameter was recorded by the Ordnance Survey in 1842, marked on their six-inch map with the small radiating lines, called hachures, that cartographers used to indicate raised earthworks. At some point between that survey and the present, the mound was levelled. Nothing remains on the ground. The field in which it stood is pasture, on a north-west-facing slope, and a person walking across it today would have no reason to pause.

What the mound actually was is not recorded. Earthen mounds of this scale in the Irish countryside could represent any number of things: the worn-down remnant of a ringfort, a burial cairn, a natural feature that attracted folklore and a name, or something else entirely. The 1842 Ordnance Survey mapping was the first systematic large-scale cartographic record of Ireland, and its surveyors noted earthworks with reasonable diligence, which is precisely why this one survives in any form at all. Without that moment of documentation, the Lissard mound would have disappeared from the record entirely when it disappeared from the landscape. As it stands, it occupies a strange middle ground: archaeologically registered, physically absent.