The mechanical work sliced through the centre of what turned out to be a souterrain, the term for an artificially constructed underground chamber or tunnel, typically associated with early medieval settlement in Ireland and used variously for refuge, storage, or concealment. The cut, three metres wide and one and a half metres deep, exposed a T-shaped, earth-cut space measuring roughly 6.6 metres by 8.8 metres across its full extent, though whether that area originally comprised one chamber or several could not be established.

Jerry O'Sullivan of University College Cork investigated the site following its discovery, recording its layout before it was back-filled. At the southernmost end of the structure, a small annexe less than a metre wide leads to an air-vent, a feature that points to deliberate, functional design rather than casual digging. More intriguing still is a creepway, a low narrow passage just half a metre wide, extending from the easternmost point in a south-easterly direction toward what may be further chambers; those chambers could not be entered or fully mapped. At the western end, a vertical shaft that had already been back-filled before investigation is thought to have served as the original entrance. With the ceiling rising no more than 1.3 metres above the spoil-covered floor at its greatest height, the interior would have demanded a crouching posture throughout. The souterrain sits in a landscape with clear early medieval associations: a possible ecclesiastical site lies nearby, and a burial ground is recorded approximately 55 metres to the east-south-east, suggesting this was once a place of some communal or religious significance.