The answer, almost certainly, is that the stones were already old and perhaps no longer legible when the souterrain was built, repurposed into the walls of a structure whose builders may have cared nothing for the writing on them. The result is that these carved stones survived, in a sense, by accident.

This particular stone, measuring 1.1 metres in length and roughly square in section at 0.3 by 0.3 metres, tells a layered story of erasure and improvisation. Ogham is an early Irish script in which letters are represented by groups of notches and strokes cut along the edge or face of a stone, most commonly recording a personal name in a formulaic genealogical phrase. On this stone, that original inscription has been almost entirely worn or deliberately erased. What remains is a second text, cut on what the scholar R.A.S. Macalister, writing in 1945, called the dexter angle, the right-hand edge of the stone's face. He dismissed it as a mere graffito, roughly scratched, and read it as DILOGONN, a reading later confirmed by Damian McManus in 1991. Whether that scratched name replaced the original with purpose, or was simply added opportunistically to a surface that had already lost its meaning, is not known. All six stones from the Ballyhank souterrain are now held in the collection of the National Museum of Ireland, and this stone has since been examined as part of the Ogham in 3D project run by the School of Celtic Studies at the Dublin Institute for Advanced Studies, which uses digital scanning to record inscriptions that the naked eye can no longer easily follow.