Beneath the tarmac, and on either side of it, lies what was once a rath, the Irish term for a roughly circular earthen enclosure, typically dating from the early medieval period and serving as a farmstead or defended homestead. At Gullaba, in level pasture close to the Slaheny River, the rath measured approximately 35 metres in diameter, substantial enough to have been clearly mapped as a circular enclosure on the Ordnance Survey six-inch map of 1846.

By the time a revised OS map was produced in 1895, a trackway already bisected the site, and that track hardened over time into the road that exists today. The fate of the southern portion was more dramatic. In the 1930s, a Captain D. B. O'Connell recorded that what remained visible was only a half circle on the north side of the road, while the southern arc had fallen away with the cliff edge. Nothing is visible above ground now. What the site may still conceal, however, is a souterrain, an underground passage or chamber of the kind often built within or beneath early medieval ringforts, used variously for storage, refuge, or ventilation of a dwelling above. Whether that feature survives intact beneath the altered ground is, for the moment, an open question.