The main focus of this study is to acquire and interpret a middle to late Pleistocene record of paleoclimate and the paleomagnetic field from nonmarine sediments in an effort to determine the effect of large and rapid climate changes on nonmarine systems. The overall stratigraphy and chronology of the sediments will be established using a multidisciplinary approach including detailed lithologic descriptions, tephrochronology, radiometric age dating, and paleomagnetic correlations. Paleoclimate will be inferred from ostracod faunal analyses, pollen floral analyses, and the geochemical analysis of ostracod shells. The paleomagnetic work will a) established a causal relationship between geomagnetic excursions and secular variations and b) established a high resolution "type section" paleomagnetic variations for the Pleistocene of western North America.