No caves are there in any geological sense. What the surveyors were recording was almost certainly a souterrain, an artificially constructed underground passage or chamber built from stone, typically associated with early medieval settlements. These structures were used variously for storage, refuge, or ventilation, and they recur across Ireland wherever early farming communities left their mark. The precise nature of what lies beneath this particular field has never been fully resolved, but the label on that old map has preserved the memory of something unusual long after the feature itself became indistinct.

The site belongs to a place known as Caherbuckaun, an anglicisation of Cathair Bhocáin, meaning the stonefort of Bocán, a personal name. A cahir, or stone-walled ringfort, is a type of enclosure common in early medieval Ireland, built to define and protect a settlement. The enclosure here is circular, defined by a well-built stone-lined bank, with the interior sitting at a slightly higher level than the surrounding land and sloping gently eastward toward a stream. At the centre of that interior lies a sub-circular area measuring roughly 21.7 metres north to south and 14.8 metres east to west, and it is this feature that is considered the likely remnant of the souterrain. A second, simpler stone enclosure sits to the southeast. Together they suggest a small cluster of activity, a place where early inhabitants organised their land, stored their goods, and dug down into the earth for reasons we can only partially reconstruct.