The Sierra Nevada Mountains form the southern portion of the Cascade-Sierra province. Like the Cascade Range, the Sierra Nevada Range formed from a chain of volcanoes along a subduction zone. However unlike the Cascade volcanoes, those that formed the Sierra Nevada Range are long extinct and buried deep within the earth forming a bed of solidified lava that is responsible for the gray granitic rocks of the Sierra. One of the best known areas in the Sierra Nevada range is Yosemite National Park.