Abstract.-- Shelton Mastodon Site (Oakland County, Michigan) was the subject of a five-year multidisciplinary study and yielded late Wisconsinan remains of algae, plants, invertebrates and vertebrates. The vertebrate faunule is comprised of: Esox lucius, Perca flavescens, Rana catesbeiana, R. clamitans, Meteagris gallopavo, Microtus pennsylvanicus, Ondatra zibethicus, Castor canadensis, Canis sp., Alces alces, Cervalces scotti (extinct), and Mammut americanum (extinct). The bones were derived from marginal lacustrine strata deposited adjacent to a forested moraine and show evidence of prolonged exposure and subaerial weathering. Nine radiocarbon dates (eight from Pleistocene and one from Holocene; seven conducted on wood and two on bone) were obtained. Dates on the principal bone-bearing strata range from 12,320 +/- 110 to 11,740 =/- 175 years before present (ybp), which corresponds to the age of the Twocreekan substage of the late Wisconsinan. Two projectile points inferred on typological grounds to be between 8,500 and 9,900 years old were found at the lower level of the Holocene bog soil overlying the Pleistocene sediments. Floral remains associated with the Pleistocene vertebrates suggest the presence of a forest dominated by conifers (mostly spruce), while the strata at a higher level contain a heterogeneous mixture of trees (mostly pine), sedges, and grasses. Some pieces of wood have gnaw marks, inferred to be those of Castor canadensis. Habitat preferences of the 10 molluscan and 25 diatom genera recovered from the associated lacustrine beds suggest eutrophic to oligotrophic aquatic conditions. Analysis of dentinal lamination indicates that the mastodon died in the spring; its stage of molar eruption and wear suggests that it was 13 to 17 years old. It is an unusual specimen in that only the right tusk developed. The molars and premolars of C. scotti are the first found in Michigan. Similarly, the remains of E. lucius, P. flavescens, R. catesbeiana, and R. clamitans are the first records for the Pleistocene of Michigan. Analyses of this site are providing detailed knowledge of the late Wisconsinan deglaciation and paleoecology of southern Michigan.