The stone that marked the hours for whatever monastic community gathered on that small island has long since been removed, leaving only the ghost of its original position and a set of measurements in a storage depot on the other side of Connacht.

The scholar R. A. S. Macalister recorded the object in 1916 to 1917, describing it as a flat slab roughly one and a half metres long, slightly wider at the top than the base, and only about ten centimetres thick. A hole pierced straight through the stone would have held the gnomon, the projecting rod whose shadow does the actual work of telling time, and below that a semicircle was carved with five radiating rays. It is a simple, functional design, the kind of mass dial or scratch dial found on early medieval church walls across Ireland and Britain, where the rays indicate divisions of the day rather than precise hours. Macalister noted its position on the south wall of the nave of St. Caimin's church, which is the sensible placement for any working sundial since a south-facing surface receives the most consistent light. The island itself, known in Irish as Inis Cealtra, carries a dense cluster of early Christian remains and is associated with a monastery founded in the seventh century. Whether the sundial dates to the early medieval period or to a later phase of the site's long use is not recorded.

The slab is now held at an Office of Public Works depot in Athenry, County Galway, catalogued under a Galway rather than a Clare monument number, a small administrative oddity that reflects how thoroughly it has been separated from its context. Anyone hoping to see it in its original setting will find only the wall.