The hollow is no accident: this is a bullaun stone, a type of early medieval stone monument found across Ireland, typically characterised by one or more bowl-shaped depressions ground or pecked into the rock. Their exact purpose remains debated, but they are generally associated with early Christian sites, and theories about their use range from the practical, grinding grain or pigment, to the ritual, collecting rainwater believed to have curative properties. This particular example is modest in scale, measuring roughly half a metre across and standing about forty centimetres high, with a central hollow some thirty-six centimetres in diameter and equally deep.

What makes this stone quietly puzzling is its absence from the Ordnance Survey maps of 1842 and 1905. Those six-inch maps were painstaking documents of the Irish landscape, and the omission of a feature from both surveys suggests either that it was not yet visible above ground, that it had been displaced or repositioned at some point, or simply that surveyors did not register it. Whether it was always associated with the church at Ballindangan or arrived there later is not recorded. The proximity to a church is nonetheless typical: bullaun stones frequently appear at early ecclesiastical sites, sometimes incorporated into boundary walls, sometimes left freestanding in a churchyard, accumulating layers of local custom around them over centuries.