It looks, on the surface, like a shallow hollow in the ground, but its regular dimensions and the stones lining its edges suggest something altogether more deliberate beneath. Archaeologists believe it may be a collapsed souterrain, an underground passage or chamber typically constructed during the early medieval period, often beneath or beside a settlement, and used variously for storage, refuge, or both.

The feature sits within the northern half of a hut site, itself embedded in a wider field system, suggesting that whoever once lived and worked this ground left behind a layered landscape, a place of daily life with both surface structures and subterranean ones. The possible souterrain was noted in D. Lavelle's archaeological survey of the Ballinrobe district, including the environs of Lough Mask and Lough Carra, published in 1994 by the Lough Mask and Lough Carra Tourist Development Association. At the time of that survey, the feature was recorded as inaccessible, its interior, if one properly exists, unreachable and unverified. That uncertainty is precisely what gives it a particular quality: it is a site defined as much by what cannot be confirmed as by what can be seen.