It is not especially large, just over a metre in length and barely half a metre wide, but cut into its face is an inscription that raises a quiet puzzle: the two lines of text are upside down relative to the cross below them. Whoever carved the words did so in an orientation that makes sense only if you imagine the slab positioned differently, or the reader approaching it from an unexpected direction.

The slab, which scholars have dated to the twelfth century on stylistic grounds, carries a Latin cross with hollowed angles and an expanding base, a form typical of the period in Ireland. Above the cross, in two horizontal lines inverted with respect to it, runs the inscription 'OR DOLAITH BERTACH'. The abbreviation 'OR' stands for the Latin orat or oratio, a standard opening formula on early Irish memorial stones meaning something like 'a prayer for' or 'pray for'. The name that follows, Dolaith Bertach, is otherwise unrecorded in historical sources, but it appears not once but twice on Inis Cealtra: the same name is carved on a second cross-slab elsewhere in St. Caimin's church. Whether that repetition reflects two separate acts of commemoration, a single patron commissioning both stones, or some other circumstance we cannot now determine, the scholar R.A.S. Macalister noted the slab in his survey published between 1916 and 1917, and Okasha and Forsyth examined it again in 2001. Inis Cealtra itself, sometimes called Holy Island, sits in Lough Derg on the Shannon and was an important monastic site associated with St. Caimin from at least the seventh century.

The slab is accessible to visitors who travel to the island, where St. Caimin's church and its surrounding monastic remains can be explored. The stone is mounted against the south wall of the nave, roughly six and a half metres from the east end, which makes it straightforward to locate once inside. The doubled name, spread across two stones in the same small church, is worth looking for on both.