It does not announce itself. To most eyes it would read simply as rubble, a slight unevenness in the interior of an already ruinous enclosure. But the shape and orientation of that hollow suggest something more deliberate beneath it, the possible collapsed remains of a souterrain.

A souterrain is an underground passage or chamber, typically built during the early medieval period in Ireland by lining and roofing a trench with stone. They are found across the country, often within or close to ringforts and cashels, and their precise function is still debated. Storage is the most widely accepted explanation, since the underground environment would have maintained a relatively stable, cool temperature suitable for preserving food. Some souterrains may also have served as places of refuge, with narrow crawl passages and concealed entrances making them difficult for intruders to navigate quickly. The cashel here, a circular enclosure defined by a dry-stone wall, is a type of fortified farmstead characteristic of early medieval Ireland, and the two features together suggest a settlement of some complexity. The qualification of "possible" attached to this souterrain is worth taking seriously. Without excavation, the stone-filled linear hollow remains suggestive rather than confirmed, the ground holding its interpretation loosely.