The carving is an equal-armed cross with expanded terminals, cut into the lintel of the loop nearest the road. Gun loops were functional military apertures, designed for defence rather than devotion, which makes the presence of a carefully executed religious symbol on the inside face quietly puzzling.

The cross is closely matched, in both size and style, by another carving on a bare vertical rockface above a holy well on the neighbouring island of Inis Oírr. That second cross is accompanied by the date 1818 and the name J. or I. Healy. These two are not isolated curiosities. A series of comparable carvings has been identified across Galway city and its environs, appearing on public buildings and private dwellings alike. Many incorporate the religious monogram IHS, a long-established Christogram drawn from the Greek name for Jesus, and a significant number carry the same Healy surname. Most of these are dated 1816, placing the probable period of activity in the mid-to-late 1810s. Whether the Inis Mór example belongs to the same hand, or simply to the same tradition, is not certain. Who Healy was, what motivated the campaign of carving, and why he marked his work with his name and a date remain unanswered questions. The carvings form a recognisable regional pattern, but the person at the centre of it has left no other trace.