Cox began studying chemistry at the University of California, Berkeley. However, after a single quarter he left school and spent three years in the United States Merchant Marine. He returned to Berkeley, but had so little interest in chemistry that his grades were too low to avoid being drafted into the United States Army. When he returned, he switched his major to geology. His research career in geology began in 1950 when he took a position as a field assistant to Clyde Wahrhaftig studying glaciation in the Alaska Range ; the pair later had a long romantic relationship. For his graduate research at the University of California, Berkeley, Cox concentrated on rock magnetism with John Verhoogen as his supervisor. Verhoogen was one of the few geologists of the time who took the hypothesis of continental drift seriously. His stance made a deep impression on Cox.