Two pointed arches, each over two metres wide, rest on a central square pillar with chamfered edges and a square capital, the whole thing carefully built and then, at some point, sealed up. The arches almost certainly opened onto a south aisle that was either planned and never fully realised, or constructed and later demolished, leaving the blocked openings as the only evidence that something larger was once intended or attempted.

The church served as the parish church of Carne, dedicated, according to a c. 1680 account by a writer named Synnott, to St Fintan Munnu, an early Irish monastic figure associated with several sites across Leinster and beyond. By 1615, when Bishop Thomas Ram, the Protestant bishop of Ferns, conducted a visitation of his diocese, the vicar here was one Apollo Waller, and the church and chancel were recorded as being in good repair. The building that survives today is a Church of Ireland structure, modest in footprint at roughly fourteen and a half metres by six, but retaining older fabric in its double bellcote on the stepped west gable and in the reused porch doorway, a pointed granite frame just under a metre wide and just under two metres high. The church continued in use until the 1950s before falling into abandonment. It sits within a subrectangular graveyard, enclosed by masonry walls on the west and north sides and by earthen banks on the east and south, the whole complex occupying a slight rise above the otherwise flat and low-lying land around it.