Beneath it, according to local knowledge, lies a stone-built chamber with a lintelled roof, its long axis running north to south, sealed off from the world and currently inaccessible.

The chamber is a souterrain, a type of underground stone passage or room found across early medieval Ireland, typically associated with ringforts and cashels and thought to have served for storage, refuge, or both. The cashel it belongs to is a stone-walled enclosure, the Irish equivalent of the earthen ringfort, and the souterrain sits within its north-eastern quadrant. No excavation record appears to exist for this one; what is known comes from local information rather than any formal investigation. The structure has suffered, too. A further collapse to the north-west suggests the underground stonework is continuing to deteriorate, quietly, out of sight.