Gothic lettering on OS maps was conventionally reserved for antiquities of some age and significance, so the name carries a quiet authority. What the label points to, however, is not a cave in any conventional sense, but a grass-covered depression sitting inside the inner bank of a rath.

A rath is a roughly circular earthwork enclosure, typically dating from the early medieval period, and thousands of them survive across Ireland in varying states of preservation. This particular example contains something more unusual within it. The depression measures roughly 11 metres north to south and between two and a half and three and a half metres east to west, and it is relatively shallow at around 35 centimetres deep. From its southern end, an arm extends eastward for another 11 metres, about 2.8 metres wide at the top and half a metre deep, before terminating in a roughly circular depression nearly five metres across. The overall shape, a long linear trench feeding into a rounded terminal hollow, suggests this may be the collapsed or heavily silted remains of a souterrain, an underground passage typically built of stone or cut into the earth, often associated with early medieval settlements and used for storage or refuge. Whether that is what lies beneath the turf here has not been confirmed, but the form is suggestive, and the place-name has preserved the memory of something subterranean long after its precise function was forgotten.