Not a representation of one, not a metaphor, but the actual vessel on which St Colm Cille sailed across from the Aran Islands. The rock, which measures approximately four metres north to south and reaches two metres at its highest western point, does carry a certain nautical plausibility in its shape, said to resemble the bows of a boat. Look closely, according to tradition, and you can make out the impression of the saint's hand on what would be the deck, the grooves along the edges worn smooth by oars, and the mark left by an anchor chain.

The folklore recorded around this stone belongs to a wider pattern of early medieval saints leaving physical traces on the Irish landscape, impressions in rock or the routes of miraculous sea voyages preserved in local memory across centuries. Colm Cille, one of the most venerated figures in early Irish Christianity, is particularly associated with sea crossings, most famously his exile to Iona off the Scottish coast in the sixth century. That he might also have crossed from Aran on a boulder, leaving the mark of a famously gigantic hand behind him, fits comfortably within the devotional logic of such traditions. The stone appears in printed sources going back at least to James Hardiman's work of 1846, and is referenced again in O'Flanagan's writings in 1927 and in Killanin's account from the mid-1940s. The writer and cartographer Tim Robinson also recorded local knowledge of the site.

The boulder sits close to two tidal holy wells in the same area, holy wells being springs or water sources associated with saints and visited for healing or devotional purposes, often on specific feast days. Visitors to those wells have a habit of taking small fragments from the boulder as relics, which explains why a stone of this size and evident resilience shows the kind of wear that accumulates not just from the sea but from generations of hands.