Abstract

Fossils were collected from the Wheeler and Marjum Formations (1,400-1,800 ft limestone and shale), from six measured sections in the House Range and one in Drum Mountains and from other localities in western Utah. Trilobites (43 species), brachiopods (eight species), mollusks (four species), and sponges (two species) are described. Three genera (Trymataspis, Utagnostus, Utaspis) and 21 species of trilobites are new. Abundant silicified specimens provide new information on morphology and ontogeny of agnostid trilobites. Evolutionary trends within Agnostidae and other families are discussed. The trilobites belong to the Bolaspidella Assemblage Zone of the standard North American Cambrian; three local assemblage subzones are named Bathyuriscus fimbriatus, Bolaspidella contracta, and Lejopyge calva.

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