This volume deals with the excellently exposed rocks of the British Tertiary Volcanic Province on the west coast of Scotland. About 50-60 million years ago a line of volcanoes was formed in response to the separation of the British Isles from Greenland during the formation of the North Atlantic. Since that time, rain, snow and the action of the sea have reduced the volcanoes to their roots, exposing their complex plumbing. Many of the historical accounts of the ancient volcanic complexes, the associated lava fields and the far-flung dyke-swarms have become classics of igneous petrology. Indeed, the Province includes many places where some of the fundamental principles of igneous petrology were established.