Picked up on aerial photography in 1973, it was recorded in 1986 as an enclosure, the kind of classification that typically signals the buried or eroded remains of a prehistoric or early medieval structure. Enclosures of that sort are common enough across Ireland, sometimes the footprint of a ringfort, sometimes the outline of an ancient field system or settlement, their shapes preserved in the soil and only legible from above. This one, it turns out, is none of those things.