During the Spathian rocks of the Thaynes Formation were still being deposited in the Sonoma Foreland Basin. The sea spread southward onto the Moenkopi mudflats and the Virgin Limestone Member of the Moenkopi Formation was deposited. The fossils below were found in the upper part of the Thaynes Formation in the Confusion Range of western Millard County.

References: Hose, R. K., and Repenning, C. A., 1959, Stratigraphy of Pennsylvanian, Permian, and Lower Triassic Rocks of the Confusion Range, West-Central Utah, A.A.P.G. Bulletin vol. 43, no. 9; Poborski, S. J., 1954, Virgin Formation (Triassic) of the St. George, Utah, Area, Geological Society of America Bulletin vol. 65; Kummel, B., 1969, Ammonoids of the Late Scythian (Lower Triassic), Bulletin Museum of Comparative Zoology Vol.137 no. 3;  Guex, J., Hungerbuhler, A., Jenks, J., Taylor, D., Bucher, H., 2005, Dix-huet nouveaux genres d'ammonites du Spathien (Trias inferieur) de l'Ouest americain (Idaho, Nevada, Utah et Californie) Note preliminaire. Bull. Geol. Lausanne 362, Numero Special, Mai 2005