A pre-trilobite shelly fauna from the White–Inyo region of eastern California and western Nevada

Abstract

A low-diversity shelly fauna occurs in the Deep Spring Formation of the White–Inyo Mountains of eastern California and in Esmeralda County, Nevada. Although poorly preserved, specimens can be recovered through acid digestion of the limestone matrix. The fauna is composed of three tubes of uncertain affinities and a hyolith.Nevadatubulus dunfeein. gen. and sp., a distinctive, randomly curved and annulated tube, is abundant and far outnumbers the remaining three elements:Coleoloides inyoensisn. sp.,Sinotubulites cienegensisMcMenamin, and the hyolith Salanytheca sp. The original composition of the faunal elements appears to have been calcite or aragonite, but recrystallization has destroyed any ultrastructure. No phosphatic elements occur with the fauna nor have phosphatic fossils been recovered from the underlying Wyman and Reed Formations or the other members of the Deep Spring Formation.The fauna occurs 1,500 meters below the first trilobite body fossils and may be coeval with faunas from the basal Cambrian Tommotian Stage of the Siberian Platform.Wyattia, the only previously described pre-trilobite shelly fossil from the region, occurs in approximately the same stratigraphic interval but was not recovered in our samples.