The collapse left a circular hole roughly half a metre across, opening into a subterranean chamber that no one had entered in living memory. A souterrain is an underground structure, typically of early medieval Irish date, built from stone or cut from earth and used variously for storage, refuge, or both. What makes this one quietly unusual is not its age but its manner of discovery: there was no deliberate excavation, no prior indication it was there. The land simply gave way.

The chamber exposed by the collapse measures approximately 2.7 metres east to west and 1.3 metres north to south, with a minimum height of around one metre, sufficient for a crouching adult but not much more. At the eastern end, a construction shaft is visible, blocked up, which would have been used during the building of the souterrain and sealed afterwards. This detail is a useful reminder that these structures were engineered with some care, not simply dug and abandoned. At the western end, a creepway, the narrow connecting passage characteristic of multi-chambered souterrains, is blocked from the inside with loose stones. A second creepway at the south-west, barely half a metre in any dimension, leads into a further chamber extending at least two metres to the north-west, the floor of which appears to be partly rock-cut rather than earth-cut. That second chamber was not entered at the time of recording, leaving its full extent unknown. A significant quantity of debris from the roof collapse had by then already fallen onto the floor of the first chamber, meaning the structure's original dimensions and condition can only be partially assessed.