It is 1.6 metres long and between 0.4 and 0.65 metres wide, slightly tapering from one end to the other, with a bevelled edge running all the way around its perimeter. The stone is broken in two places, and there is no inscription, no carved cross, no decorative knotwork, nothing to indicate whose remains it once marked. It is, in other words, a slab that has shed every clue it might once have carried.

Canon Island takes its name from the Augustinian canons who established a house there, most likely in the twelfth or thirteenth century. The church in which this slab lies is part of that monastic complex, and the graveslab almost certainly dates from the medieval period of the community's occupation. A second medieval graveslab lies nearby, beneath the sedilia, the recessed stone seats built into the south wall of a chancel where priests would rest during parts of the liturgy. That two such slabs survive in the same small interior, both unidentified, speaks to how thoroughly time and weather have erased the human particulars of the site. The bevelled edge on the first slab is a relatively common feature of medieval funerary stonework, giving the slab a modest architectural finish, but without carving or lettering there is no way to place it within any particular tradition or workshop.