Ordovician vertebrates from Western United States / Denison, Robert H. (Robert Howland), 1911-1985. text [Chicago] : Field Museum of Natural History, 1967. eng p. 131-192 : 24 cm. Caption title. "December 29, 1967." Includes bibliographical references (p. 188-192). Fieldiana series has been published as Geological Series by Field Columbian Museum (1895-1909) and Field Museum of Natural History (1909-1943), and as Fieldiana: Geology by Chicago Natural History Museum (1945-1966) and Field Museum of Natural History (1966-). Vertebrates, Fossil -- West (U.S.) Paleontology -- Ordovician. Paleontology -- West (U.S.)