A rectangular depression, eight metres long and five metres wide, runs east to west across the northern part of the enclosure's interior. It looks, at first glance, like evidence of a souterrain, an underground stone-lined passage or chamber built during the early medieval period, often used for storage or refuge. But the uncertainty here is half the point. Two other disturbed areas nearby suggest more recent digging, possibly for rubbish disposal, which means the hollow could be the trace of an ancient feature or simply the consequence of someone, at some point, finding a convenient place to bury unwanted material.

The site was noted as early as 1914, when a researcher named Neary recorded what was described as a spoon-shaped hollow that appeared to indicate a dug-out souterrain. The phrasing is cautious even then, the word "appears" doing considerable work. The ringfort itself, a class of roughly circular enclosure typically defined by an earthen bank and ditch and associated with early medieval farming settlement in Ireland, remains the larger context for whatever this depression represents. Whether the souterrain was ever fully excavated, partially robbed of its stonework, or simply never existed in the first place is a question the ground has not yet answered.