No earthwork survives, no ring of stones, no subtle rise in the field. The only evidence that something was once here is a dark circular line, roughly thirty metres across, visible in infra-red aerial photography and nowhere else.

The feature is a ring-ditch, a type of circular enclosure that typically survives in the archaeological record as a ditch cut into the subsoil, long since levelled and built over or simply worn away. In many cases ring-ditches are thought to mark funerary or ceremonial sites from the prehistoric period, the ditch itself once surrounding a burial mound or flat grave. What the infra-red photography reveals is a cropmark, a phenomenon where buried features affect the moisture content of the soil above them, causing the crops or vegetation growing there to behave slightly differently from the surrounding ground. From the air, and especially through infra-red imaging, that difference registers as a tonal variation, a ghostly outline of something that ceased to be a physical presence long ago. The site was identified and described by Michael Connolly as part of his doctoral research into prehistoric settlement in the Lee Valley, completed at University College Cork in 2008, and it sits within a broader landscape that he examined for traces of early human activity in an area of marshy land prone to flooding.