The slab is modest in its dimensions, roughly the length of a tall person and not much wider than a pair of shoulders, yet its inscription connects two of the most significant Connacht surnames of the medieval and early modern period, cut into limestone at a moment when Gaelic Ireland was still finding ways to mark its dead in the old manner.

The stone, located in the chancel of the friary at Baile Chláir, the town known in English as Claregalway, was recorded by Bradley and Dunne in 1992. It measures 1.76 metres in length, 0.51 metres in width, and 0.14 metres in thickness. The inscription, rendered in the Roman lettering conventional for the period, reads: PRAY FOR THE SOVLES OF MORTAGHLEOGHELLY AND HIS WIFE MARY BVRKE XIII IVN 1685. The name Murtagh O'Kelly, spelled out phonetically across the line break as MORTAGHLEOGHELLY, reflects the Irish form Muircheartach Ó Ceallaigh, a name long associated with the territory of Uí Maine in east Galway. Mary Burke belonged to another prominent Connacht family, the Burkes of County Galway and Mayo. The date, 13 June 1685, places the stone well into the period following the Cromwellian wars, when Catholic burial and commemoration, though practised openly in places, carried a complicated legal and social weight. The chancel of a friary, the eastern section of the church traditionally reserved for the religious community and liturgical use, was a prestigious location for a burial slab, suggesting the O'Kellys retained some local standing.