This project involves detailed taxonomic, biostratigraphic, and paleoenvironmental analyses of previously unstudied Lower Cambrian fossil faunas and stratigraphic units in Central Nevada (Shoshone, Toiyabe, and Toquima Ranges). This research will provide the following: 1) detailed descriptions of the Lower Cambrian stratigraphic units; 2) descriptions of the local Lower Cambrian faunas; 3) paleoecological analyses of Lower Cambrian facies; and 4) biostratigraphic correlations with other Lower Cambrian units in western North America. This information will then be applied to more general problems of the Early Cambrian including: 1) the temporal pattern of diversification during the Cambrian radiation event; 2) tests of the Grand Cycle hypothesis of sediment accumulation in the Lower Cambrian of western North America; 3) biogeographic relationships of Early Cambrian metazoan faunas; 4) reconstruction of the phylogenetic relationships of the early metazoan taxa; and 5) documentation of the influence of changing paleoecologies on the actual nature of the radiation event (as well as its apparent record). In short, the goal of this project is to produce the detailed stratigraphic and paleontologic data critical to understanding Early Cambrian metazoan evolution and the processes responsible for the Cambrian radiation event.