Craig Manson, who as assistant secretary of the Interior Department under Gale Norton was responsible for overseeing the U.S. Fish and Wildlife Service and the National Park Service, resigned yesterday. According to reports, he left to take a teaching position at the University of the Pacific's law school. Manson, deeply disliked by environmentalists, was a staunch critic of the “critical habitat” provision of the Endangered Species Act, a section of the law that governs what land must be preserved in order to save species from extinction.