These twin depressions are what remains visible of a souterrain, an underground stone-built passage or chamber constructed during the early medieval period, typically used for storage, refuge, or both. Most souterrains are invisible unless you know to look for them; this one announces itself only through subsidence, the slow collapse of the earth above.

The souterrain sits at the edge of a level area within the south-western quadrant of a cashel, a type of early medieval stone-walled enclosure, roughly analogous to a ringfort but built in stone rather than earthen banks. The positioning is typical: souterrains are frequently found at the margins of such enclosures, often running beneath or just inside the surrounding wall. The two exposed lintels, each still in situ, suggest the underground structure retains much of its original form beneath the surface, even as the covering soil has settled and shifted above it.