Ffynnon Cegin Arthur is a noted chalybeate spring in forestry land to the south of Llanddeiniolen. Found by going to the very end of the lane from Penisarwaun through Waun, crossing the stile on the left-hand side and then following the track lined on either side by tall trees through forestry land for around two hundred yards. The well is ten or twenty yards off the track on the left a little before a stream. Chalybeate springs are noted for their high mineral content, in particular iron, and were resorted to for health cures. First identified and named in the late fifteenth century, from the Latin chalybs, steel, the popularity of chalybeate wells spread, reaching its peak in the seventeenth and eighteenth centuries. During the nineteenth century, the popularity of such wells began to decline, as other cures took their place. Local legend is that King Arthur still uses this well to live forever. Some say that he uses it as a forever wandering spirit.