Locals know it as St. Patrick's Stone, and it sits just twenty-five metres from St. Patrick's Well, set on its edge and absorbed into the boundary wall as though it has simply always been there. What makes it worth a second look are the grooves: numerous deep vertical cuts, each around 25 centimetres long and 3 centimetres deep, scored into the face of the stone and along its upper and lower edges. The explanation the stone carries in local memory, that these are the finger-marks of St. Patrick himself, is the kind of origin story that tends to accumulate around ancient and inexplicable markings. The archaeological reading is rather different, and rather older.

The cuts closely resemble a type of stone known in French prehistory as a polissoir, literally a polisher, found in association with megalithic monuments and understood to be a surface used for grinding and sharpening tools or weapons. Similar stones are recorded elsewhere under names like grooved stones or sword-sharpening stones, though the dating of any individual example remains difficult to establish with certainty. In 1938, a pupil at Carrick National School recorded a piece of local folklore about this very stone for the Irish Schools' Collection, a nationwide project in which children gathered oral traditions from their communities. The account is careful and observant: the writer notes the size of the stone, the position of the marks on its face and top edge, and adds, almost in passing, that to his eye they looked like Bronze Age markings. It is a remarkably level-headed assessment from someone who, by his own account, had grown up being told the marks were something else entirely.