At Toureen Peacaun, a small carved slab, broken along its bottom edge and of irregular shape, has been set into the top of the wall that surrounds the well. It is easy to overlook; at roughly fifteen centimetres high and nineteen centimetres wide, it is barely larger than a human hand.

Despite its modest dimensions, the slab carries a deliberate and carefully incised Latin cross on its front face, a simple linear form cut into the centre of the stone and running down towards the broken edge. The back is plain. Scholars Okasha and Forsyth, writing in 2001, catalogued it as part of a wider corpus of inscribed stones from the site, listing it as Toureen Peacaun 35. A holy well, in Irish tradition, is a spring or water source associated with a saint or with sacred healing properties, and such sites frequently accumulated carved and inscribed stones over centuries, some placed as votive objects, others simply gathered and incorporated into later structures as the site evolved. The cross-slab at Toureen Peacaun appears to belong to this broader pattern, a fragment of early devotional carving that ended up embedded in the fabric of the well enclosure rather than standing independently.

The stone is visible in the wall of the well enclosure itself, which means a visitor who knows to look for it should find it without great difficulty, though its small size and broken condition mean it could pass unnoticed against the surrounding stonework.