Step closer, and the illusion shifts. What appears to be a plain earthen rampart turns out to conceal a mortared stone wall, a caiseal, running through its core, about one and a half metres thick and faced on both sides with packed earth. At the eastern side, an arched entrance pierces the enclosure: round-headed, carefully proportioned, with sides rising to about one and a half metres and the full height to the apex reaching just over two metres. When the historian William Carrigan described it in 1905, he considered the arch probably one of the oldest specimens of its class in Ireland. Inside, the ground is smooth and largely undisturbed, except for the low foundations of a small church oriented east to west, barely nine metres long, and a single grave belonging to a Mr Ryan of Kilferagh House, who had died some years before Carrigan's visit. The local people, he noted, had no name for the place and no memory of it ever being used as a burial ground.

The question of what this enclosure actually is has not been cleanly resolved. Carrigan treated it as a genuinely ancient ecclesiastical site, possibly connected with the nearby church of St Fiachra, which lies about two hundred and ninety metres to the east. The first Ordnance Survey map of 1839 to 1840 shows trees growing inside the enclosure, and by the 1945 to 1946 revision it was being marked simply as a tree-ring. The proximity to Kilfera House, about four hundred and sixty metres to the northeast, points toward a different explanation. The round-headed doorway with its imposts is an early twelfth-century architectural form, but it is now thought likely that the mortared walling is considerably more recent, and that the arch itself was removed from another structure, possibly St Fiachra's church, and rebuilt here as a folly. Follies of this kind, featuring salvaged medieval stonework arranged to suggest antiquity, were a recognised feature of designed landscapes around Irish country houses from the eighteenth century onward. If that is what happened here, someone went to considerable trouble: the arch is carefully built, the enclosure is geometrically regular, and the effect, especially with the concealed stone core of the bank, is quietly convincing.