In each hollow rests a smooth, oval stone, nestled in a pool of collected rainwater. Locally these stones are called 'butter lumps', and the boulder itself goes by the name 'The Petrified Dairy', a title that says a good deal about how the surrounding community chose to make sense of it. A bullaun stone, to give it its proper term, is a boulder or outcrop bearing one or more of these artificial cup-shaped depressions, a type found widely across Ireland and generally associated with early Christian or pre-Christian ritual activity. This one is unusual in the density of its association: a holy well, Tobarfeaghna, lies roughly sixty metres to the north-east, and the boulder formed part of the devotional circuit, or 'rounds', performed there. A church and burial ground dedicated to St Fiachna are close by to the north, and a second bullaun stone stands only thirty-five metres to the south.

The folklore gathered in 1937 and 1938 from Shelbourne School in Gortrooskagh gives the place its peculiar texture. The seven hollows were read as keelers, shallow dairy vessels, and the oval stones as pats of butter, the whole arrangement understood as the petrified remnant of a woman's dairy, frozen in stone by St Fiachna as punishment for stealing milk from her neighbours' cows. According to the account recorded by Mícheál Ó Tuama, the saint pursued the woman on horseback after turning her dairy to stone, crossed a stream, and on the far hillside overtook her and turned her into stone as well; a standing stone, described as a fine gallán of six feet, was said to mark the spot. In one version of the story, the saint had a sword, took a swing at the fleeing woman, missed, and split a large boulder in two, which could also be seen in the landscape. The woman had been carrying a spancel, a loop of rope used to hobble cows during milking, and from the búircín, a small knob at the end of it, a tree was said to have grown on the bare hillside. The stones in the keelers were not to be disturbed; a man who took one home to cure a sick cow was said to have lost his entire herd by morning, the pebble returning to its hollow of its own accord. A separate strand of the same tradition called the boulder 'The Rock of the Warts', prescribing a ritual of seven anti-clockwise circuits, prayers at each basin, and the application of the collected water to the affected skin.