The Tropic Shale was deposited in the Sevier Foreland Basin during Cenomanian time, as part of the Western Interior Seaway. Ammonites are found in exposures of this formation in what is now Grand Staircase-Escalante National Monument and around the towns of Orderville and Alton.
References: White, C. A., 1877, Report upon the Invertebrate fossils collected in portions of Nevada, Utah, Colorado, New Mexico and Arizona, by parties of the expeditions of 1871, 1872, 1873, and 1874, U. S. Geographical and Geological Explorations and Surveys West of the 100th Meridian Report (Wheeler), vol. 4, pt. 1; Stanton, T. W., 1893, The Colorado Formation and it's Invertebrate Fauna, U.S.G.S. Bulletin 106; Hyatt, A., 1903, Pseudoceratites of the Cretaceous: edited by T. W. Stanton, U.S.G.S. Monograph 44; Swenson, A. J., 1962, Anisoceratidae and Hamitidae (Ammonoidea) from the Cretaceous of Texas and Utah, B.Y.U. Geology Studies Vol. 9, pt. 2
Euomphaloceras
septemseriatum Zone
Jim
Jenks
collected
the
following from the Tropic Shale
in the area around Henrieville, Garfield County, Utah.
Some of the first Cephalopods reported from the state of Utah. C.
A. White described fossils collected by members of the Wheeler Survey
on Upper Kanab Creek, the taxonomy has changed quite often
since they were first reported.
Metoicoceras
geslinianum (d'Orbigny) 1850
reported as Buchiceras
swallovi (Shumard)
by White in 1877
and as M.
whitei, M.
kanabense
and M. gibbosum by Hyatt in
1904
M. kanabense was named after Kanab
Creek which flows near Alton
Euomphaloceras
septemseriatum (Cragin) 1893
reported as Acanthoceras? kanabense by Stanton
in 1894
and as Kanabiceras septemseriatum (Cragin)
in the 1957 Treatise
again, named after Kanab Creek
Pseudocalycoceras
angolaense
(Spath) 1931
Sciponoceras gracile
(Shumard) 1860
reported by Stanton in 1893 as Baculites
gracilis Shumard
Allocrioceras annulatum
(Shumard) 1860
reported by White in 1877 as Helicoceras
pariense
named after Paria Creek which
flows near Tropic
Worthoceras
vermiculus (Shumard)
1860
Top: Sciponoceras gracile
(Shumard)1860
Lower Left & Lower Center: Metoicoceras
geslinianum (d'Orbigny) 1850
Right Middle: Allocrioceras annulatum
(Shumard) 1860
Lower Right: Euomphaloceras
septemseriatum (Cragin) 1893
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