It is not merely decorative; the stone is thought to be a reused cross slab, repurposed as a structural quoin at some point in the building's history, which quietly suggests a longer and more layered occupation of this ground than the surviving walls alone might imply.

The building is known locally as Teampall na Naomh, meaning the Church of the Saints, and sits near the centre of an early ecclesiastical enclosure at Cill Mhuirbhigh. It is a small early Christian oratory, oriented east to west as was conventional for early Irish churches, measuring just 4.75 metres in length and 3.45 metres in width. An oratory of this type is essentially a single-cell stone chapel, among the earliest forms of Christian architecture in Ireland, often associated with monastic or hermetic settlement. What survives here is limited: only the lower portions of the walls remain standing, a doorway in the north wall has been robbed of its stonework, and the east wall retains only the base of what was once a single-light window. Scholars O'Flanagan and Westropp both recorded the site, with references dating to 1927 and a later edition of Westropp's work in 1985.

The site sits within a wider enclosure that predates the oratory itself, and the presence of the possibly reused cross slab suggests the area was significant even before the oratory took its current form. Visitors to Inis Mór will find the remains modest in scale, but the density of early medieval material concentrated in this small area rewards careful attention. The cross incised into that corner quoin is easy to overlook, but it is one of the more quietly thought-provoking details on the island.