What makes this one quietly interesting is that it began as an accident of geology. The limestone was already wearing away naturally, and at some point someone looked at that weathering depression and decided it was worth finishing off. The result is a modest but deliberate hollow, roughly 30 centimetres across and 14 centimetres deep, set into exposed bedrock rather than into a moveable stone.

Bullauns are found across Ireland in a variety of contexts, often near ecclesiastical sites or holy wells, and their original functions are not always clear. They may have been used for grinding, for collecting rainwater thought to have curative properties, or for purposes that have simply not survived in the documentary record. The Legan example fits neatly into a recognisable pattern: approximately 44 metres to the north-east lies a holy well, suggesting that this small cluster of features, the carved stone and the well, once formed part of a local devotional landscape, even if the precise nature of that connection is no longer legible. The site was noted by English in 1971, and the proximity of the two features in an area of naturally outcropping rock gives the place a quiet coherence that is easy to miss from the road.