1. Stratigraphic distribution and zonation of Jurassic (Callovian) ammonites in southern Alaska Author/Creator: Imlay, Ralph W. 1908-1989. (Ralph Willard) Publication/Creation: Washington : U.S. Govt. Print. Off, 1975 Resource Type: Book Is Part Of: U.S. Geological Survey professional paper, no.832-839. Access & Availability: Loading
2. Stratigraphic distribution and zonation of Jurassic (Callovian) ammonites in southern Alaska Author/Creator: Imlay, Ralph W. 1908-1989, (Ralph Willard), author Publication/Creation: Washington : United States Department of the Interior, Geological Survey, 1975 Resource Type: Book Access & Availability: Loading