That label almost certainly refers to a souterrain, an underground stone-lined passage or chamber of early medieval date, typically used for storage or as a place of refuge. A near-identical enclosure is shown on the opposite, western bank of the same river, in Knockaskeagh townland. Two ringfort-like enclosures facing each other across a river is an unusual enough arrangement; what makes it stranger still is what happened when someone went looking.

When the eastern-bank site was inspected in 1998, no above-ground trace of the enclosure remained. The map evidence from 1836 is clear enough, the hachured lines indicating an earthwork that surveyors could see and record, but within roughly 160 years it had disappeared entirely from the landscape. The souterrain it once contained, or sheltered, or simply happened to neighbour, was presumably already underground and therefore less vulnerable to levelling. Whether the enclosure was ploughed out, built over, or simply eroded away is not recorded. The western-bank enclosure's current condition is not noted either, leaving a small but genuine puzzle about what, if anything, survives on that side of the water.