Early and Mid Cambrian trilobites from the outer-shelf deposits of Nevada and California, USA

A latest Early Cambrian and earliest Mid Cambrian polymeroid trilobite fauna, consisting of 16 genera and 25 species, is reported from the peritidal deposits of the Mule Spring Limestone and outer-shelf deposits of the Emigrant and Monola formations of Nevada and California. The Mid Cambrian fauna includes a new genus, Tonopahella, and four new species, T. goldfieldensis, Oryctocephalus americanus, Onchocephalites claytonensis, and Syspacephalus variosus. The peri-Gondwana species Oryctocephalus orientalis, Oryctocephalites runcinatus, and Paraantagmus latus are recorded in Laurentia for the first time.