Local lore adds more about Merlin. He stayed on for a while after Vortigern left. When he left himself he filled a golden cauldron with treasure and hid it in a cave, blocking the entrance with a stone and a heap of earth. The treasure is intended for one particular person, a youth with blue eyes and yellow hair. When he approaches, a bell will ring and the cave will unblock itself. Other treasure seekers have been repulsed by storms and sinister omens.
p89 in Geoffrey Ashe’s ‘The Landscape of King Arthur’ (1987).