The earth simply gave way, and what opened up beneath was a chamber tall enough for a person to stand upright in, with drystone walls and a ceiling of stone lintels. Nobody had been looking for it.

The structure sits within a rath, a roughly circular earthwork enclosure of the kind that was commonly built as a farmstead during the early medieval period, roughly between the fifth and twelfth centuries. Souterrains, the underground passages and chambers associated with many such sites, were typically built from carefully laid dry stone and roofed with large flat slabs. Their precise function is still debated; they may have served as cool stores for dairy produce, places of refuge, or both. This one ran on a northwest to southeast axis. More striking than its architecture, though, was what was found inside: a possible ogham stone. Ogham is an early Irish script in which letters are represented by a series of notches and strokes cut along the edge of a stone, and such stones are found in significant numbers across the southwest of Ireland. Whether this particular stone was inscribed there originally or brought in from elsewhere at some later point is unknown. There are now no visible remains of the souterrain above ground; what the machinery opened, time and the landscape have since closed again.