Around 1982, a plough caught the capstone of a souterrain, the large flat stone sealing the roof of the structure, and displaced it, briefly exposing the chamber below. The opening was subsequently infilled, and today there is no visible surface trace of anything at all.

A souterrain is a type of dry-stone underground passage or chamber, typically associated with early medieval settlement in Ireland, often built adjacent to a ringfort and used for storage, refuge, or both. The brief accidental exposure here confirmed that at least one such chamber survives at Gneeves, though its full extent is unknown. Roughly a hundred metres to the south, aerial survey has identified a levelled circular enclosure, the kind of low, flattened earthwork that was once a ringfort, the defended farmstead of an early Irish family. The two features almost certainly belong to the same settlement, the souterrain functioning as a subterranean annex to the enclosure above ground. That the enclosure is itself levelled, and the souterrain now sealed beneath pasture, means the entire complex has effectively vanished into the landscape, surviving only as a set of coordinates and a piece of local memory about a plough striking stone.