Taxonomy and biostratigraphic significance of some Middle Cambrian trilobites from the Conasauga Formation in western Georgia

Abstract

Biostratigraphic correlations of the Conasauga Formation in the southern Appalachians have been hindered by unreliable trilobite taxonomy. New fossil collections and re-examination of type specimens allow revision or confirmation of assignments for several Middle Cambrian trilobite taxa. These revisions reveal sufficient relationships with trilobites outside the region to place fossiliferous strata in Floyd County, Georgia, into the Oryctocephalus and Bolaspidella assemblage zones of the Middle Cambrian section defined for the Great Basin. Trilobite taxa considered are: (Agnostida) Baltagnostus centerensis (Resser, 1938) and Peronopsis cf. P. cuneifera (Barrande, 1846); (Ptychopariida) Alokistocare americanum (Walcott, 1916), Elrathia antiquata (Salter, 1859), Asaphiscus gregarius Walcott, 1916, and Glyphaspis cf. G. capella (Walcott, 1916).