An east-facing slope of rising ground overlooking a river marks the location of a medieval church that has entirely disappeared below the surface, leaving no visible trace at ground level. What makes the place quietly unsettling is what the Ordnance Survey Namebooks recorded in 1840 alongside the church ruins: a children's burial ground. These sites, known in Irish as cillíní, were used for the interment of unbaptised infants and others considered ineligible for consecrated ground. They were places of sorrow and discretion, often attached to the ruins of older ecclesiastical sites, and Foildarrig fits that pattern precisely.

When the Ordnance Survey's officers recorded the site in the nineteenth century, there were still wall-footings visible, and the dimensions noted by O'Flanagan in 1930 give some sense of the original structure: roughly 5.7 metres north to south and approximately 12 metres east to west, with walls about a metre thick. That footprint is consistent with a small early medieval or later church. Close by, to the south-west, a bowl-barrow survives, one of the rounded earthen burial mounds associated with the Bronze Age. The proximity of prehistoric and early Christian remains on the same piece of ground is not unusual in the Irish landscape, where sacred use of a location could persist or be reinvented across millennia, but it concentrates a great deal of layered meaning into an unremarkable hillside.