St Davids 15 is a rough boulder of spotted dolerite, carved on one face. It is now located in The Lapidarium at Porth y T'r, St Davids Cathedral (NPRN 306). The stone was first mentioned in 1856 when it stood in a field known as Parc-y-berth, on the north side of the south wall. The stone is one of four (see NPRNs 423520, 423522, 423523) in the vicinity of Penarthur Farm, the location of a possible chapel and cemetery site (NPRN 423519). The stones are generally accepted to have been originally placed upright around a holy well to the east of the small parcel of land belonging to the Bishop and known as Maenarthur, where the stones were first recorded. It is unclear whether this was Ffynon Penarthur or Ffynnon Parc-y-Berth.

Dimensions are given as 50.5cm height x 38cm width x 25.5cm diameter. The boulder is carved in low relief with a roundel with closed circuit interlace in the centre (forming an incised, linear, equal-arm cross) surrounded by a fret-pattern border. The interlace is identical to that in the centre of the cross-head of St Davids 8 (NPRN 423477). The Viking-age border fret-pattern is similar in style to St Davids 14 and 16 (NPRNS 423520 & 423522), and also comparable to St Davids 9 (NPRN 423498). The carving Is thought to date to the second half og=f the 10th or the 11th century.

N Vousden, 30 October 2018