Known locally as "an gadaidhe dubh", the dark thief, it almost certainly began its existence as a voussoir, one of the wedge-shaped stones forming a curved arch, in a 12th-century Romanesque church that preceded the current structure. It ended up re-embedded in the east gable of the nave, stripped of its original architectural context, its face rubbed nearly smooth by centuries of exposure. Nearby, on the external face of a lintel above a south-wall window, is a carved human figure that scholars have tentatively identified as a sheela-na-gig, a category of enigmatic figurative carvings found on medieval Irish and British churches whose precise meaning remains debated. There is also, set into the north-east corner of the nave, a quoin stone inscribed with what appears to be a Greek cross within a square frame, likely displaced from the same earlier Romanesque building.

The ruins, which stand near the eastern end of a graveyard, are associated by tradition with a convent founded by St Gobnet, an early Irish saint venerated in this part of Cork. The church itself consists of a nave measuring roughly 19 metres east to west, with a chancel added at the eastern end whose arch jambs, as the scholar O'Kelly noted in 1952, are built of carefully squared brown sandstone blocks fitted so tightly they carry the unmistakable character of 12th-century craftsmanship. The walls otherwise stand to near full height. A doorway and slit window set into the west gable face inward rather than outward, implying that a structure once abutted the exterior of that wall. Charles Smith, writing in 1750, described this feature as a steeple that was "ready to fall with age"; by the mid-19th century it had become a heap of stones entirely. The nave contains a shallow arched recess in the north wall and a small wall press opposite in the south, details that speak to the everyday practical life of a functioning medieval parish church.

The place remains active, if in an unconventional way. Five pilgrimage stations are laid out around the ruin, electric lights have been fixed to the church walls in connection with this devotional use, and in 1993 a PVC-windowed lean-to was added against the north wall of the nave to shelter a donated set of Stations of the Cross. The interior is now occupied by burials spanning the 18th, 19th, and 20th centuries. Visitors approaching with an archaeological eye should look closely at the south wall windows, whose cusped round-headed lights contrast with the simpler slit window at the west end, and at the chancel's east wall where a reused ogee-headed lintel was pressed into service during a later repair, a small sign of the long, improvised life of the building.