For many years past the author has studied the later Mesozoic deposits of California, Oregon, and other western States, and more recently he has reworked some of their more complete sections in the Coast Ranges of California. From all parts of the succession, large collections of fossils have been made; these have been deposited in the California Academy of Sciences, San Francisco, where they have been studied in part. In this work the author has had the cordial cooperation of Dr. G. Dallas Hanna, curator of paleontology at the Academy of Sciences; Dr. Olaf P. Jenkins, of the State Division of Mines, and various other friends. The facilities and the support of the Academy of Sciences have greatly aided, not only in the field work and in the collection of materials, but also in the library work and the study necessary in the preparation of the present contribution. In . . .