There is a circular enclosure in the townland of Park, County Waterford, that has effectively vanished from view while remaining on the map. Roughly 55 metres in external diameter, it sits on a gentle north-east-facing slope in pasture ground, yet nothing of it is visible at ground level. The only way to know it is there at all is through the 1840 edition of the Ordnance Survey six-inch map, where it appears as a faint circular trace, the cartographers recording something that the landscape has since swallowed entirely.

What makes the site more than just an invisible ring on old paper is what came out of the ground during land reclamation work: a possible bullaun stone, now kept nearby. Bullaun stones are boulders or slabs, usually of uncertain age, into which one or more cup-shaped basins have been worn or pecked, and they turn up across Ireland in association with early ecclesiastical sites, ringforts, and ancient enclosures. This particular example measures roughly 1.75 metres long and between 0.45 and 0.8 metres wide, with a shallow basin about 25 centimetres across and only 5 centimetres deep. Its modest proportions and the circumstances of its discovery, churned up during agricultural improvement rather than excavation, leave its connection to the enclosure tantalisingly unconfirmed. Whether the stone was placed within the enclosure deliberately or simply shared the same ground by accident is a question the site cannot yet answer.