What emerged was a souterrain, an early medieval underground stone passage or chamber typically associated with nearby ringforts or settlement sites, used for storage, refuge, or both. This one is modest in scale, roughly the size of a large wardrobe laid on its side, but its survival in even partial form is quietly remarkable given how easily such structures are lost to agriculture, quarrying, or simple time.

The chamber measures approximately 2.75 metres north to south, 1.3 metres east to west, and just over a metre in height. Its walls are built from random rubble and corbelled, meaning the stones are laid so that each course projects slightly inward over the one below, allowing the structure to close overhead without a true arch. The technique is ancient and efficient, requiring no mortar and no specialist cutting of stone. A single cracked lintel remains in place at the southern end, a telling detail given that the northern half of the chamber has collapsed inward and is now filled with earth and loose stone. The proximity of a large limestone quarry next door raises an obvious question about whether quarrying activity contributed to that collapse, though no firm conclusion has been drawn on that point.