The Wyoming Province of the western United States contains well-exposed proterozoic to latest Archean igneous rocks that were accreted to the North American Craton during Pre Cambrian times. The paleomagnetic technique offers the possibility of determining the location of the origin of the Wyoming Province and tracking its subsequent approach and assembly. This project will collect paleomagnetic data from a number of mafic dikes and plutons using modern techniques and 40 Ar/39 Ar age dates to establish crystallization ages and cooling histories. Results are expected to make considerable improvements to the present understanding of the Wyoming Province and to provide critical data needed to follow the assembly of the large precambrian super-continents.