Article: Middle Devonian brachiopods from the Roberts Mountains, central Nevada
J. G. Johnson
Middle Devonian stratigraphy in the Roberts Mountains is briefly reviewed and Middle Devonian limestone strata below the Devils Gate Limestone are assigned to a brachiopod-rich formation, the Denay Limestone (new name). Walcott's Skenidium devonicum is made type species of a new dalmanellid genus Vallomyonia and his Cryptonellal circula is assigned to Leptathyris. The brachiopods of the Leptathyris circula zone (new name) and the Pentamerella subzone in the lower part of the Denay Limestone are described and illustrated and their palaeontologic evidence suggests an Eifelian assignment. Fifteen species are described, fourteen from the Leptathyris circula zone in the Roberts Mountains. Three new species and one new subspecies are Pentamerella wintereri, Hadrorhynchia eurekaensis, Echinocoelia denayensis, and Warrenella kirkipraekirki. Cyrtinacea is proposed as a superfamily.