That hollow, measuring roughly forty centimetres across and eighteen centimetres deep, is not accidental erosion. It is a bullaun, a deliberately formed basin cut or ground into a boulder, and it belongs to a tradition of such stones found at early Christian and pre-Christian sacred sites across Ireland. What makes this particular example quietly remarkable is the detail recorded when it was examined in 1989: local people were still using it to cure warts.

Bullaun stones are found throughout Ireland, often close to early medieval churches or monastic sites, and their precise origins and original purposes remain matters of debate among archaeologists. Some were likely used as mortars for grinding; others accumulated layers of ritual significance over centuries, becoming associated with cursing, blessing, or healing. The water that collects in the basin after rain is frequently considered to hold curative properties, and wart-curing is one of the most commonly recorded folk uses. At Tonygarrow, that folk practice had not faded into memory by the late twentieth century. The stone sits within an ecclesiastical enclosure, the kind of roughly circular or oval boundary, often formed by an earthen bank or wall, that typically marks the limits of an early Irish monastic or church site. The combination of sacred landscape and living folk custom, persisting together in a small Wicklow townland well into living memory, is the kind of continuity that official records rarely capture so plainly.