Initial reports of the Deep Sea Drilling Project : a project planned by and carried out with the advice of the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES). Volume LXXIV, covering Leg 74 of the cruises of the drilling vessel Glomar Challenger, Cape Town, South Africa, to Walvis Bay, South Africa, June to July, 1980 / editors Jan H. Bakeslee, Marianna Lee ; prepared for the National Science Foundation, National Ocean Sediment Coring Program, under contract C-482, by the University of California, Scripps Institution of Oceanography