An Upper Cambrian fauna of Franconian age is present in the Peerless formation in a unit of sandy glauconitic dolomite that formerly was called the Ute Pass dolomite. This fauna includes species of Idahoia, Ellipsocephaloides, and Ptychaspis. The overlying Manitou formation contains in its basal portion species of four lowermost Ordovician zones of Utah: the B, C, D, and E or F zones. Sixteen species are described, two of which are new. Distribution of the zones suggests that the Manitou formation is older in the N. part of the outcrop area and overlaps the truncated Upper Cambrian rocks from N. to S.