It is easy to miss. The cross is modest in scale and unannounced, but its form is precise: wedge-shaped terminals flare at the ends of each arm, a detail that suggests deliberate craftsmanship rather than casual scratching.

The stone itself measures 1.12 metres long by 0.32 metres high, and its proportions have led Dr J. Waddell to suggest it may originally have served as a door lintel, later reused as building material in the church wall. If that is correct, the cross may have been carved when the stone held a more prominent position, framing an entrance rather than sitting flush in a corner. Professor Rynne considered the carving possibly 19th century in date, which would place it well outside the early medieval period one might instinctively associate with a site called Cill Mhuirbhigh, meaning roughly "the church of the sea inlet". That more recent date, if accurate, makes the piece quietly interesting in a different way: not an ancient monument but a later addition to a much older fabric, someone in the 1800s choosing to mark a stone of a ruined or working church with a simple devotional sign.