The Carlile Shale (Middle Turonian, about 84 meters thick) is made up of shales, shaley chalks and chalky limestones deposited during the regression of the Greenhorn cyclothem. Stewart (1990b) reported Cretalamna appendiculata, Cretodus crassidens, Cretoxyrhina mantelli, Squalicorax falcatus, and Ptychodus whipplei from this formation. Russell (1993) does not include P. whipplei, however, and adds Ptychodus mammilaris to Stewart's list.