Seven ogham stones, some of them centuries old when they were placed there, had been built into its walls and roof. Six of the nine roofing slabs bore ogham inscriptions, the ancient script that uses a series of notches and strokes along a central stemline to render an early form of Irish. One larger stone had cracked at some point in the distant past and was being propped upright by a seventh. When workmen broke into the structure in 1838 while building a field boundary, they found bones and skulls alongside the inscribed stones.

The souterrain, marked simply as 'Cave' on Ordnance Survey maps, had lain undisturbed long enough for its contents to become something of a mystery. In 1940 the Office of Public Works removed all seven ogham stones and re-erected them close to a nearby public road, where they remain today. The underground chamber itself was filled back in and left no trace on the surface. This particular stone, one of five whose individual details have been recorded, stands 1.3 metres high and up to 23 centimetres wide. Its inscription runs along both edges and across the top, though the top portion broke off at some point before modern scholarship reached it. R. A. S. Macalister, writing in 1945, read the surviving text as NIOTTVRECC MAQI [. .]GNI, a partial personal name formula of the kind common on early Christian period memorial stones, recording descent or patronage. The damaged section means the full name remains incomplete. More recently the stone was included in the 'Ogham in 3D' project run by the School of Celtic Studies at the Dublin Institute for Advanced Studies, which uses digital scanning to document inscriptions that centuries of weathering continue to erode.