Published by the American Geophysical Union as part of the Geodynamics Series, Volume 15. Marine sedimentary rocks now exposed on land are mainly deposits of shallow shelf seas, although ancient deep-sea sediments do occur in the mountains. The Alpine radiolarites and pelagic lime-stones have been compared to Recent ocean oozes, after the exploration of the H. M.S. Challenger during the second half of the last century, but the ship that revolutionized the earth science was its modern namesake, D/V Glomar Challenger. Thanks largely to the 15-year effort by the Deep Sea Drilling Project of the Joint Oceanographic Institutions Deep Earth Sampling Program, we have made quantum jumps in our understanding of the history of the ocean. Time has been added as the 4th dimension to oceanography, and the birth of a new inter-disciplinary science, paleoceanography, was announced with the recent publication of the publication of the first issue of a journal of that name.