‘Doon the watter’ epitomises the traditional lure for the Glaswegian of the Firth of Clyde and the dramatic islands that once formed ‘Buteshire’. Goat Fell, not quite a Munro but worth every one of its 2,866 feet, is chief of the granite hills that give north Arran its ‘Sleeping Warrior’ outline from the Ayrshire coast. Bute, though less hilly, has its own craggy knolls and sweeping sandy bays. The Cumbraes, Holy Island and distant Ailsa Craig, too, all have their own distinctive and well-loved shapes. This booklet explains how they were fashioned by over 600 million years of geological time.