The cross incised into its surface is an early type, with T-shaped terminals, meaning the arms of the cross end in a flat, squared-off bar rather than tapering to a point or broadening into a more elaborate form. It is a detail that looks simple until you realise how precisely it places the object in time.

On stylistic grounds, the slab has been dated to somewhere between AD 600 and 800, a period when early Christian communities across Ireland were beginning to mark their dead and their sacred spaces with inscribed stones of exactly this kind. The material is shale, a fine-grained sedimentary rock that splits into workable slabs, and whoever carved it worked on a relatively modest piece: 0.42 metres wide at its broadest, tapering slightly toward the base, and no more than a few centimetres thick. The cross is centrally positioned on the face of the stone, deliberate in its placement. The dating attribution comes from Timoney, writing in the late 1960s and early 1970s, whose analysis placed the slab within that formative early medieval window when the visual language of Christian carving in Ireland was still finding its conventions.

The slab stands roughly five metres south of the south-west corner of the old church at Kilmacowen, within the graveyard that surrounds it. It is an easy thing to walk past without pausing, which is perhaps the most telling fact about it: a stone that has occupied the same few square metres of Sligo ground for over a thousand years, through every iteration of the landscape around it, doing nothing more than standing and being old.