What the collapse exposed was a souterrain, an underground stone-built passage and chamber of the kind constructed in early medieval Ireland, typically associated with settlement sites and used variously for storage, refuge, or both. The ground had held the secret intact for perhaps a thousand years before a routine day's farming interrupted the arrangement.

What survives, and what was recorded after the collapse, follows the classic pattern of souterrain construction in miniature. The initial void revealed a dry-stone walled chamber, roughly 1.3 metres by 1.05 metres, whose original form is now uncertain given the damage. Leading off its north side is a creephole, the term given to the deliberately tight connecting passages that force anyone moving between chambers to slow down and squeeze through, a feature understood to have served a defensive function. This one is a particularly compact example: just 0.65 metres long, 0.5 metres wide, and 0.45 metres high, its roof formed by a single lintel stone and one side by a single stone set upright on its edge. Beyond it lies the main chamber, roughly rectangular and oriented southeast to northwest, approximately 2.85 metres in length and about a metre wide. Its walls of near-vertical dry-stone construction stand around 1.35 metres high and are roofed by four lintel stones laid end to end. The floor carries a layer of fine clay silt, which suggests the chamber floods periodically, though it was dry at the time of survey.