1. Jurassic (Oxfordian and Late Callovian) ammonites from the western interior region of the United States Author/Creator: Imlay, Ralph W. 1908-1989. (Ralph Willard) Publication/Creation: Washington : U.S. G.P.O., 1982 Resource Type: Book Is Part Of: U.S. Geological Survey professional paper, no. 1232-1239. Access & Availability: Loading
2. Twin Creek limestone (Jurassic) in the western interior of the United States, Author/Creator: Imlay, Ralph W. 1908-1989. (Ralph Willard) Publication/Creation: Washington : U.S. Govt. Print. Off, 1967 Resource Type: Book Is Part Of: U.S. Geological Survey professional paper, no. 537-540. Access & Availability: Loading
3. Characteristic marine Jurassic fossils from the western interior of the United States Author/Creator: Imlay, Ralph W. 1908-1989. (Ralph Willard) Publication/Creation: Washington : U.S. Govt. Print. Off, 1948 Resource Type: Book Is Part Of: U.S. Geological Survey professional paper, no. 214. Access & Availability: Loading