The Klamath Mountains are an arcuate structural province of Ordovician to Late Jurassic oceanic - and island arc - affinity rocks that were accreted to the western margin of North America during Mesozoic plate convergence. However, the actual tectonic processes during accretion are not well established. Recent work has suggested that parts of the Condrey Mountain Schist exposed in the north-central Klamath Mountains may be an eastward continuation of the Franciscan Complex. If confirmed, this would indicate that the Klamath rocks have been thrust about 100 km over the Franciscan Complex along shallow faults. This project will provide geochronologic, petrologic and isotopic data to more firmly establish the Condrey Mountain - Franciscan correlation and to allow a more detailed account of the accretion processes involved.