"Carraig an tSeipeil", the Rock of the Chapel, is not a building and never was one, but that is precisely the point. Along its western face, a natural ledge of bedrock runs at roughly waist height, level enough to serve as an altar, and the ground in front opens onto a flat field bounded by a stone wall to the south. The whole arrangement, accidental in geology but purposeful in use, is the kind of site that rewards a second look.

Mass rocks are outdoor sites where Catholic priests celebrated the Mass clandestinely during the Penal Law era, a period broadly spanning the late seventeenth and eighteenth centuries when the public practice of Catholicism was suppressed under British legislation. Congregations gathered at remote outcrops, hillsides, and field boundaries, often with a flat stone serving as the altar. At Carraig an tSeipeil, the natural ledge on the western side of the rock would have performed that function, with the spire-like form of the outcrop itself perhaps lending the gathering a sense of the sacred space it was substituting for. The site sits about ten metres west of the road on the southern side of Pipe Hill, and was documented by archaeologist Tony Miller in 2014, having been brought to his attention by Hilary Bishop, who has been researching Mass rocks across the area.

The rock is visible from the road, its triangular profile distinct enough to pick out against the hillside. The natural ledge on its western face, at about waist height, is the detail worth noticing once you are close, since it transforms what might otherwise seem like an unremarkable outcrop into something with a clear functional logic.