It is a single wall, eighteen metres long and nearly three metres at its highest point, built from random-rubble limestone and now forming part of the southern boundary of the graveyard beside the Convent of Mercy. The openings for windows and a doorway have been blocked with masonry, a statue of St Joseph occupies one of those blocked opes on the interior face, and a plaque erected in 1896 records that beneath the ground here lie the remains of a parish priest, laid at the gospel side of the altar without headstone or inscription. The wall is, in other words, doing several things at once: holding a boundary, sheltering graves, carrying memorials, and quietly preserving the outline of a building that no longer exists.

The 1842 Ordnance Survey six-inch map labels the site "Old R.C. Chapel" and shows it as a rectangular structure with a projection on the northern side, set slightly off-centre to the east. By 1937, the same map marks it only with a symbol for a site of antiquity, which suggests the building had been a ruin for some time by then. It was replaced during the 1830s by a new church on the main street. The cut-limestone edging stones visible within one of the blocked openings may indicate an even earlier structure on the site, possibly connected to a medieval nunnery. The 1896 plaque names the Rev. James Roche, parish priest from 1779 to 1807, whose burial here without any marker was evidently thought significant enough to correct, nearly ninety years later. A second memorial stone, in Latin, commemorates someone named Donegan, who died in 1774. The lane running along the southern side of the wall was called Chapel Lane on the 1842 map and had been renamed Mill Lane by 1906, reflecting the shift in local memory from the chapel to the corn mill further along the lane.