The fragment, which appears to read HATA, was found resting on the wall of one of the cells at the site, and the question of what it actually is has never been satisfactorily resolved. Is it an ogham inscription, a form of early medieval writing in which letters are represented by notches and strokes cut along a central line, or is it something far more mundane?

The first recorded observation came in 1869, noted by Brash in his 1879 publication, and a further sighting was reported by Harris in 1939. Whether these two scholars were looking at the same stone is itself uncertain. R. A. S. Macalister, the prolific cataloguer of Irish ogham stones, was sceptical of both accounts, proposing in 1945 that the fragment was most likely a piece of grooved paving slab rather than any kind of inscribed monument. His intervention did not settle the matter so much as add another layer of doubt. The scores that seemed to spell something meaningful to one observer looked like functional stonework to another, and without a definitive examination the fragment remains suspended between inscription and coincidence.