Near Castle in County Cork, there is a holy well that no surveyor has been able to locate in the field, its position swallowed by encroaching vegetation and the waterlogged ground that surrounds it. Holy wells, as a category, occupy a peculiar space in the Irish landscape; they were sites of pre-Christian and later Catholic veneration, associated with healing, patron saints, and the ritual of "patterns", communal gatherings held on a saint's feast day. They tend to persist, quietly maintained by local custom across centuries. This one, apparently, did not.