Eight plaques in total are distributed across the interior and exterior walls, and their mix of subjects, saints, a crucifixion, a Virgin and Child, a Latin inscription, and a winged cherub above the doorway, suggests an accumulation of material over time rather than any single decorative programme. The cherub over the entrance was misidentified by the antiquarian W. G. Wood-Martin in 1882 as a representation of the rising sun, which gives some sense of how weathered or ambiguous the carvings had already become by that point.

The plaques carry a date of 1730 on one stone, carved in false-relief beneath a cross with expanded terminals, and the same year appears on a reused keystone set over a doorway in the adjacent T-plan dwelling house, where it flanks the Crofton family crest, a stalk of wheat, beneath the motto "DAT DEUS INCREMENTUM" (God gives the increase). The Crofton connection runs throughout the site; the wheat stalk appears again on the exterior plaque of the chapel, and a fuller version of the family arms, showing a lion passant guardant with helmet and crest, is worked into the tympanum of the western entrance to the house, carved by a different hand and probably also eighteenth century in date. The plaques of St David, St Paul, and St Peter are similar enough in size and style to suggest a single sculptor, though they may date anywhere from the eighteenth to the nineteenth century. A Latin inscription on the eighth plaque reads, in translation, something close to: "For it is God that the image teaches, but the image itself is not God; look upon it, but worship in your mind what you see in it", a conventional early modern defence of religious imagery. A twentieth-century marble angel has been added in the arched opening between the St David and St Paul carvings. The plaques are mentioned in Lady Morgan's novel "The Wild Irish Girl", written at Longford House and published in 1840, which places them firmly in the landscape before the mid-nineteenth century.