They are cairns, a general term for mounds of heaped stone that in an Irish context most often served a funerary or memorial purpose in prehistoric times, though the precise age and function of these two examples remains unrecorded. What is clear is that whoever placed them here chose the spot deliberately, and the elevation that makes the site so conspicuous to anyone standing on it has also, perhaps, kept it undisturbed.

The larger of the two mounds measures eight metres by six metres and stands roughly forty centimetres above the surrounding ground, with loose stone still visible within its fabric. Its smaller neighbour is six metres by four metres and slightly lower at thirty centimetres. Both sit atop ground classified as marginal, given over now to rough grazing, which suggests the limestone outcrop has never been particularly productive farmland. That may partly explain why the mounds have survived at all. The site was recorded during a survey of the Lee Valley area carried out in 1996 and 1997.