Turonian age rocks are the most widespread cephalopod bearing rocks in Utah. The Tropic Shale in the south, the Frontier Formation in the north and northeast, and the Tununk , Ferron Sandstone , and Juana Lopez Members of the Mancos Shale in eastcentral Utah. These rocks were deposited in the Sevier Foreland Basin .

References: Cobban, W. A., 1951, Scaphitoid Cephalopods of the Colorado Group, U.S.G.S. Professional Paper 239; Cobban, W. A., 1976, Ammonite Record from the Mancos Shale of the Castle Valley-Price-Woodside Area, East-Central Utah, B.Y.U. Geology Studies Vol.22, Pt.3; Molenaar, C. M., and Wilson, B. W., 1990, The Frontier Formation and Associated Rocks of Northeastern Utah and Northwestern Colorado, U.S.G.S. Bulletin 1787-M; Molenaar, C. M., and Cobban, W. A., 1991, Middle Cretaceous Stratigraphy on the South and East Sides of the Uinta Basin, Northeastern Utah and Northwestern Colorado, U.S.G.S. Bulletin 1787-P;  Kennedy, W. J., Cobban, W. A., and  Landman, N. H.,  2001, A Revision of the Turonian Members of the Ammonite Subfamily Collignoniceratidae from the United States Western Interior and Gulf Coast, American Museum of Natural History Bulletin 267.