What he found, or rather what he fell into, was a roughly circular collapse about a metre across and less than a metre deep, with a possible lintel stone lying at an angle over what appears to be a shaft descending more than a metre further into the earth.

Souterrains are dry-stone underground passages or chambers, typically associated with early medieval settlement in Ireland, and generally thought to have served as cool storage spaces or places of refuge. They were built to be invisible from above, which is precisely why so many of them survive, unrecorded and undisturbed, beneath ordinary agricultural land. The Ballygorteen example came to light not through excavation but through the ordinary pressure of a plough loosening a few stones and causing the ground to slump. Since that moment, the hollow has gradually silted up again, and the shaft, if that is what it is, may now be largely obscured. Based on the angle of the fallen lintel and the direction of the collapse, the underlying passage is thought to run roughly northeast to southwest, sitting about three and a half metres west of a field boundary running north to south.