It is easy to mistake for a geological curiosity, but the arrangement is deliberate: this is a boulder-burial, a type of prehistoric funerary monument in which a large capstone is raised on low supports, sometimes covering human remains placed beneath. The form is closely associated with the Bronze Age in Ireland, and examples cluster particularly along the south-west coast.

This particular boulder measures roughly 1.4 metres east to west and 1.15 metres north to south, with a thickness of about 0.55 metres. It rests on at least three support-stones, the tallest of which reaches 0.5 metres on the eastern side and 0.4 metres on the west, giving the capstone its slight downward lean to the west. The monument has not remained entirely untouched by later land use; its northern edge has been partially absorbed into a field boundary, the kind of quiet alteration that happened to countless prehistoric structures as farming shaped and reshaped the landscape over centuries. That it survives at all in recognisable form, on a small island in one of Kerry's most dramatic sea inlets, makes it a quietly unusual presence.