It looks partly natural, partly shaped by human hands, and that ambiguity turns out to be exactly the point.

When archaeologists Seán P. Ó Ríordáin and Máire Mac Dermott excavated the site in 1950, they found something quietly layered beneath and around that mound. Three cists, which are small stone-lined burial boxes typically used in prehistory to contain human remains, were uncovered alongside two pit burials. The stony material of the possible cairn itself was found lying directly over one of those cists, suggesting a deliberate act of covering or marking. The excavators cautiously identified the whole arrangement as a possible Bronze Age burial mound, though the partly natural character of the rise left the question open. What makes the site stranger still is that the story did not end in the Bronze Age. At some later point, a rath was constructed on the same spot. A rath is a circular earthen enclosure, most commonly associated with the early medieval period in Ireland, and its builders almost certainly knew they were placing their settlement on ground that already carried meaning. Whether that was deliberate or incidental, the effect is a site where two very different periods of Irish prehistory and early history are stacked on top of one another, each reusing the same modest rise on a remote Mayo plateau.