It was not alone: fifteen ogham stones in total were found at Ballyknock being used as roofing material for a souterrain, the kind of stone-lined underground chamber that appears across early medieval Ireland, typically used for storage or refuge. Using carved standing stones to cover such a structure was not unheard of, but finding fifteen of them together is extraordinary.

Ogham is an early Irish script, usually carved as a series of notches and strokes along the edge of a stone, and most inscriptions follow a simple formula recording a person's name and lineage. This particular stone, standing just over four feet tall and a little over a foot wide, carries an inscription along its dexter edge and across the top. The lettering is worn and slightly chipped, which has produced some disagreement between scholars. R. A. S. Macalister, whose monumental 1945 corpus of ogham stones remains a foundational reference, read it as BOGAI MAQI BIRACO, meaning roughly "of Bogai, son of Biraco". Damian McManus, working from the same stone in 2004, arrived at a slightly different reading, BOgaI MAQI BIrAC, with the final characters uncertain. The names themselves are obscure, leaving us with a memorial to people whose stories have otherwise vanished entirely.

The stone is now held permanently in the Stone Corridor at University College Cork, a long vaulted passageway that houses one of the finest collections of ogham stones in the world. Many of the stones displayed there were recovered from similarly unexpected contexts, repurposed and buried before being retrieved by later generations with different ideas about what they were worth.