That label was almost certainly pointing to something far more deliberate than a natural hollow: a souterrain, an underground passage or chamber built by hand, typically during the early medieval period, and used variously for storage, refuge, or concealment. Today, nothing visible remains at the surface to betray its existence.

The site sits close to the hilltop, roughly 180 metres north-east of a rath, the circular earthwork enclosure associated with early Irish farmsteads and settlements. The proximity is telling. Souterrains were frequently constructed in direct association with raths, often accessible from within the enclosed area, and the relationship between the two features here suggests they may have belonged to the same settlement complex. By the time the second edition of the six-inch OS map was printed in 1899, the underground structure was apparently well enough known locally to earn a cartographic note, even if its true character was rendered only as "Cave". At some point between then and the compiling of the county archaeological inventory in 1993, whatever surface evidence once existed, whether a depression, a stone-lined entrance, or a collapse hollow, had disappeared entirely.