Set into the underside of a damaged corbel, a corbel being a projecting stone bracket used to support a structure above it, is a weathered sheela-na-gig. These carvings, typically depicting a naked female figure in an exaggerated pose, appear across medieval Ireland and Britain on churches, castles, and other stone structures, and their precise purpose remains disputed. They are old, strange, and not especially well explained by history. Finding one built into a church porch, rather than displayed in a museum case, has a particular quality of quiet incongruity.

The corbel's original home is not known with any certainty, though it is considered likely to have come from somewhere nearby. One suggestion, put forward by J. Mannion in a 2008 article published in the Journal of the Galway Archaeological and Historical Society, is that it may once have belonged to Templemoyle, a medieval church site in the same general area of east Galway. Mannion's article was principally concerned with early medieval ecclesiastical history in the region, tracing what he identified as an Anglo-Saxon monastic connection, and the sheela-na-gig appeared as a related detail within that broader argument. Whether it genuinely originated at Templemoyle, or simply ended up in Newcastle by some other local route, cannot now be determined from the stone itself, which is damaged enough that reading it requires patience and a decent light.