From end to end the Coastal division of the North American Cordillera, including the Sierra Nevada, Cascade Mountain system, the British Columbia Coast range, the Alaska, Saint Elias, and other ranges, comprising an area more than six times that of the Alps of Europe, is now proved to inclose granitic masses of great size and importance. Most of them are of post-Archean dates, and it is even probable that the greater number belong to post-Paleozoic epochs.* Many of the Californian stocks and batholiths and a few batholithic masses in the state of Washington have been carefully studied. Much work has been done, too, in the yet more extensive granitic fields of Alaska and British Columbia; but this work has generally been incidental to long reconnaissance surveys, wherein detailed investigations could not be profitably undertaken. In the Sierra Nevada the post-Paleozoic granitic rocks—granodiorites—are largely, if not entirely, of Mesozoic age. . . .