In a field in Ballyhays, County Kildare, something ancient is visible only from the air, and only under the right conditions. When crops grow unevenly, their roots reaching differently into soil disturbed long ago by buried ditches, they betray what the surface conceals. The result is a cropmark, a ghostly outline pressed into the green or golden field, and at Ballyhays that outline describes a ring-ditch formed by two concentric fosses, that is, circular ditches dug into the earth, one inside the other.

Ring-ditches of this kind are generally understood to be the eroded or ploughed-down remains of prehistoric funerary or ceremonial monuments, sometimes the last traces of a burial mound whose earthen bulk was long since scattered by centuries of agriculture. The aerial photograph that first recorded this site, catalogued as GB89.AF.11 and compiled by Dr. Gillian Barrett, also captured the cropmark of a nearby curvilinear enclosure, a roughly circular enclosed space defined by its own fosse. Whether the two features belong to the same period of activity is unknown; the chronological relationship between them remains uncertain. Adding further texture to the landscape are cropmarks of plough-levelled field boundaries in the vicinity, older divisions of land now as invisible at ground level as everything else here, legible only to a camera looking straight down from altitude.

There is nothing to see at ground level today. The monument has been levelled by ploughing over an unknowable number of years, and the field presents itself as ordinary farmland. What exists now is essentially a record, an image taken from above at the right season, preserving the shape of something that would otherwise have disappeared entirely without leaving a name or a story behind it.