What it revealed was a souterrain, an underground stone-lined passage or chamber typically associated with ringforts and used for storage or refuge, sitting quietly in the northern half of a ringfort at Glashaboy in County Cork, roughly ten metres inside the enclosing bank.

The collapse created an opening of about one metre by half a metre, just large enough for archaeologists Ann Lynch and Mary Cahill of University College Cork to investigate part of what lay below. The accessible chamber measured approximately two and a half metres in length and one and a half metres in width, oriented on a northwest to southeast axis. The construction was mixed: the southeastern end was cut directly into bedrock, while the rest was earth-cut. More intriguingly, the chamber appeared to continue in a north-northeasterly direction, possibly running beneath the ringfort's own bank. Fallen earth blocked any further progress, so the full extent of the underground structure was never established. The site was subsequently backfilled, leaving the question open.