What the machinery exposed was not a plain agricultural stone but a piece of prehistoric rock art, carved with a cluster of concentric circle motifs of the kind found scattered across Atlantic Europe and dating, in most comparable Irish examples, to the Neolithic or Bronze Age. The find location alone gives some sense of how loaded this landscape once was: a south-facing slope above Clew Bay, with Clare Island and Achill Beg visible to the south-west, the southern end of Achill Island to the west, and Croagh Patrick rising on the far side of the bay to the south-east. Whether the people who carved the stone were responding to that panorama in some deliberate way is impossible to say, but it is hard not to notice the coincidence.

The boulder, an irregular chunk of Old Red sandstone roughly 75 by 70 by 50 centimetres, carries its decoration on one main face: a band of three close-set concentric circle motifs, with a fourth motif of concentric arcs conjoined to two of them, and a possible fifth partly hidden under lichen. The largest of the circular motifs, around 17 centimetres in overall diameter, is particularly striking because of its three-dimensional quality. At its centre sits a pronounced raised boss, approximately 5.5 centimetres across and some 2 centimetres high, encircled by three deep concentric grooves that have a rough, corroded texture. This kind of raised central boss is relatively uncommon in Irish rock art, where motifs are more typically pecked or incised flush with the stone surface. On the opposite face there is another feature, a slightly concave raised area enclosed on one side by rough concentric arcs, though it remains uncertain whether this is a further carved motif or simply the result of natural weathering in the stone. The discovery was reported immediately to the National Monuments Service and the National Museum of Ireland, and the boulder was transferred to the NMI, where it is held under acquisition number NMI 2022:60, currently undergoing specialist recording and conservation.