The foundations of Capel Gwladys are located in open moorland about 3 km NNW of Gelligaer Roman fort (NPRN 93007).
The remains of the chapel, a low spread stony bank densely overgrown with bracken measuring roughly 14m (E-W) by 7m overall (by the 1960s), has been replaced (before 1979) by low consolidated walling of coursed slabs. This measures internally 12.75m long (east by west) and 5.9m wide, the foundation wall 0.9m thick and 0.25m high. The original outline of the chapel is believed to have consisted of nave, chancel and western tower. A slab with incised ring-cross found here in 1906 (NPRN 301370) is now located in the porch of Gelligaer parish church. A modern cross has been erected inscribed "Capel Gwladys circa 450 AD", a replacement for the original.
The chapel is set within a sub-rectangular enclosure defined by a low stony bank 1m-1.5m wide and averaging 0.25m high. On the south side a short length of it extends to 2m wide, rising to 0.6m high. Overall the enclosure measures some 75m (N-S) by 72m. It is portrayed on early Ordnance Survey maps and is visible on air photos.
The chapel and enclosure are associated with a much larger surrounding earthwork enclosure (225487).
Additional sources:
OS record: ST19NW1.
RCAHMW AP94-CS 0767-8
RCAHMW AP945105/49

David Leighton, RCAHMW, 17 November 2015