Dominated by Renalcis and Epiphyton. Proaulopora.
Archaeocyathids (important taxa only): Mackenziecyathus, Siderocyathus, Keriocyathus, Archaesycon, Molybdocyathus.

Abstract of ref. 1995:
Abstract: Several new occurrences of archaeocyathan-calcimicrobe-built reefs have been discovered in the upper Harkless Formation (Bonnia-Olenellus Zone) in
Esmeralda County, Nevada. Initial analyses of the paleoecology of these reefs show that the community structure consisted of several genera of archaeocyaths acting as the framework entity with calcimicrobes acting as the binding entity. Since the reefs are found in the upper Harkless, they are among the youngest known
metazoan-built reefs in western North America and represent the last pulse of metazoan reef building prior to their global disappearance in the Middle to Late
Cambrian. The mechanism or mechanisms that contributed to the demise of the metazoan reefs are unknown; therefore, we are studying these reefs in part to test hypotheses concerning the collapse of the Early Cambrian metazoan reef communities. 

These reefs contain the typical assemblage of Early Cambrian reef dwellers such as trilobites, echinoderms, and brachiopods; however, at one locality coralomorphs
are conspicuously present. These coralomorphs are approximately 12 cm long by 18 cm wide, are found scattered throughout the reefs, and constitute only a small percentage of the reef by volume. The coralomorphs have definite polygonal corallites which do not share walls, and resemble cerioid tabulate corals without obvious tabulae. Septa occur as obscure processes that project into the center of the corallites, dividing the corallites in half. These coralomorphs are similar to the genus Rosellatana, Kobluk, 1984 from the Lower Cambrian Cassiar Mountains of British Columbia. 