THE SCILLY ISLANDS 195 the old Cornish name of St. Michael's Mount repre- sents that rock as having once stood in the centre of woodland. It is impossible to say when or how the Scillies first became insular, whether by sudden cataclysm or by gradual erosion ; the latter seems more likely, but tradition has preferred to speak of a sudden catastrophe, such as that which is supposed to have overwhelmed Cardigan Bay. There is a story which says that a member of the Trevilian family was only saved from the inrush of waters by the speed of his horse, which struggled inland from the pursuing waves, reaching a rocky cleft on the shore at Perranuthnoe. It is possible that slow erosion may have paved the way to some such immediate disaster, such as that caused by a great storm in 1099, when, according to the Saxon Chronicle, many villages and churches were swept away. It was this storm, accompanied perhaps by a tidal wave, that converted the estates of Earl Godwin into the dreaded Goodwin Sands ; and it may have caused tremendous damage, not definitely recorded, in the West. But another tradition attributes the formation of the islands to magic. It was said, by those who placed Arthur's last great battle in the West of England, that, after the fight was over, the triumphant Mordred chased the King's despairing followers to the extreme limits of Lyonesse, where they lay " between the devil and the deep sea," like the Israelites pursued by Pharaoh. The cruel Mordred was close at their heels, rejoicing in the prospect of exterminating the last remnant of Arthur's Round Table, when suddenly the wizard Merlin appeared in his path. The maofician raised his hand and summoned the elements to his aid. The earth began to heave and the rocks to split; waters came rushing into
