Garnwnda (Carn Gwnda) is named after Saint Gwyndaf Hen (Gwyndaf the Aged), who presumably used it as a nice quiet spot for a bit of hermitage and religious introspection. He lacked some of the sympathy for nature that some of the other Celtic saints had. He was returning from Fishguard one day and was just crossing one of the (many) streams in the area, when a fish leapt up and frightened his horse. Poor Gwnydaf was thrown to the ground and broke his leg. He cursed the brook so no fish would ever live in it again.
(mentioned in volume 3 of Baring-Gould’s ‘Lives of the British Saints’ 1913).