Measuring roughly six metres by five, it is built from loose, flat slabs of the kind that litter the scree around the peak, which means it could be ancient, or it could be relatively recent, or something in between. Archaeologically speaking, its antiquity is described as dubious, a quietly damning phrase that places it in an awkward category: too prominent to ignore, too ambiguous to classify with confidence.

By 1945, the writer Richard Hayward noted it simply as a pile of stones, which suggests it had not yet acquired any formal identity. At some point after that, climbers began modifying it for use as a shelter, adapting whatever original form it held into something more immediately practical. It is not alone in this role; two other shelters also occupy the summit. The most visually dominant feature nearby is an iron cross, erected just north of the cairn in 1950, which now serves as the landmark most walkers are making for when they haul themselves to the top. The cairn, by contrast, tends to go unremarked.

What makes the site quietly interesting is precisely this layering of purposes and uncertainties. A structure of unknown origin, possibly prehistoric or possibly not, has been absorbed into the working landscape of a busy mountain summit, sitting a short distance from a mid-twentieth-century religious monument, all of it perched on scree at the highest point in Ireland. Whether the original builders intended anything ceremonial, funerary, or simply practical is a question the stones themselves refuse to answer.