What makes it worth a second look is not the structure itself, modest as it is at roughly four metres by three, but a stone resting against its western wall. The object is a bullaun stone, or at least something closely resembling one: a roughly worked slab of stone bearing a shallow circular hollow ground into its upper face. Bullaun stones are found across Ireland, often near early ecclesiastical sites or holy wells, and the depressions in them were almost certainly made deliberately, though their precise purpose remains a matter of debate. They are sometimes associated with ritual use, with water collecting in the hollow thought to carry curative or protective properties.