 Heat generated from the Farallon Plate subducting below the North American Plate led to the creation of an island arc of volcanoes on the west coast of proto @-@ North America between the late Devonian and Permian periods . Later volcanism in the Jurassic intruded and covered these rocks in what may have been magmatic activity associated with the early stages of the creation of the Sierra Nevada Batholith . 95 % of these rocks were eventually removed by uplifted @-@ accelerated erosion . 
