The block is easy to overlook; it measures only 0.6 metres long and 0.4 metres wide, and stands just 0.3 metres high. But set towards its eastern end is a carefully worked circular basin, roughly 16 centimetres across and 10 centimetres deep, smoothed and shaped with a precision that distinguishes it from any accidental hollow in the stone.

This is a bullaun stone, a type of ancient carved rock found widely across Ireland, typically associated with early Christian ecclesiastical sites. The basins were almost certainly functional, used for grinding or perhaps for holding water in a ritual context, though the full range of their uses remains debated. What is consistent is their setting: bullaun stones appear again and again near churches, graveyards, and holy wells, suggesting they occupied a meaningful place in the devotional life of early medieval communities. At Kilmacanoge, the stone's position on the footprint of the vanished church wall places it directly within that tradition. The church nave it once adjoined has disappeared at ground level, but the bullaun remains, a point of continuity in a landscape that has otherwise been substantially altered.