The piece is modest in size, roughly half a metre by twenty centimetres, but it carries a surprising amount of detail for something that was apparently repurposed as building rubble.

The fragment is a rectangular carved panel, and scholars have suggested it likely came from the side or front of a sarcophagus, the term for a stone coffin, often elaborately decorated, associated with high-status burials in medieval and early modern Ireland. When a cross wall was constructed in 1804 to connect the south-western side of St Mary's with the adjoining graveyard wall, this older piece was incorporated into the new stonework. Three decorative panels remain visible. The rightmost contains part of a quatrefoil window motif, a four-lobed geometric form common in late medieval ecclesiastical carving. The two panels to the left depict ogee-headed windows, a distinctively curved arch shape, pointed at the top and concave on each side, fashionable in Gothic and late Gothic design. The researcher Bradley, writing in 1980, recorded and catalogued the piece, placing it in its sixteenth-century context.

What makes this fragment quietly odd is its situation. Rather than being preserved as a discrete object, it was built flush into a functional wall, where it has remained ever since, its carved surfaces facing outward, legible to anyone who knows to look. At St Mary's, the wall connecting church to graveyard is the thing to seek out, and the panel sits within it, a piece of funerary sculpture absorbed into everyday stonework without ceremony.