It is not much to look at in purely physical terms, but locally it carries a name, Tobar na Caillí, and a story to go with it. According to tradition, a woman from the nearby townland of Bó Bhrocháin dreamed that she would be cured of pains in her bones if she found a particular spot on this shoreline. She came, she found it, and the pothole has been associated with healing ever since. Holy wells in Ireland are rarely elaborate structures; more often they are modest features of the landscape, a spring, a stone basin, a depression in rock, given meaning by repeated visits and the weight of local memory.

What makes this site stranger still is its relationship to the surrounding geology. Between Tobar na Caillí and a second well roughly 310 metres to the south-east run two dykes of porphyry, a type of rock in which large crystals of quartz are embedded in a finer matrix, producing a distinctly veined appearance where the formations cut across the shoreline. These two dykes run north to south, and according to local tradition, as recorded by the cartographer and writer Tim Robinson, they were understood not as geological features but as the roads that the saints once travelled on their way to the Aran Islands, visible out in the bay to the west. The idea of a physical road running beneath or across the sea, marked in stone, connecting a place of curing to a destination of pilgrimage, gives the whole stretch of coastline a quietly layered quality that sits somewhere between sacred geography and folk geology.