Stratigraphic distribution of archaeocyathids in the Silver Peak range and the White and Inyo mountains, western Nevada and eastern California

Archaeocyathids from the White and Inyo Mountains and Silver Peak Range of California and Nevada occur in the middle one-third (approximately 2,000 feet) of the Lower Cambrian section as defined by the olenellid biozone. Three assemblages are recognized and can be correlated throughout the region by stratigraphic position. The lowest known occurrence of an archaeocyathid, Ethmophyllum, is found approximately 1,000 feet above the lowest olenellid trilobite Fallotaspis. The upper archaeocyathid assemblage, which is characterized by Coscinocyathus, occurs approximately 3,000 feet below the uppermost olenellid fauna.