Abstract

Lake Bonneville is the most studied pluvial lake in North America. At its highest stand in the late Pleistocene, the lake inundated several thousand square kilometers of western Utah, extreme eastern Nevada and Southern Idaho. The mammalian fauna collected from the shoreline deposits of the lake is composed of a diverse late Pleistocene (Rancholabrean NALM A) assemblage. There are at least 15 large mammalian taxa recognized of which ten are extinct (Arctodus simus, Equus sp., Platygonus compressus, Camelops hesternus, Bison bison subsp., Navahoceros sp., Symbos cavifrons, Bootherium bombifrons, Mammut americanum, Mammuthus columbi), one locally extirpated (Canis lupus) and four are extant (Vulpes vulpes, Ursus americanus, Ovis canadensis, Odocoileus hemionus). Most fossils have been collected from the commercial sand and gravel quarries that line the Wasatch and Oquirrh Mountain fronts. All specimens are believed to be associated with the final rise and fall of Lake Bonneville (Bonneville Lake Cycle). The mammals seem to be indicative of open park lands or grasslands situated in coniferous forests.