During the Middle Pleistocene about 300,000 years ago, volcanism shifted westward and constructed the nearly symmetrical stratovolcano of Mount Price. Episodic eruptions produced andesite and dacite lavas, as well as pyroclastic flows from Peléan activity. Later, the volcano was overridden by the Cordilleran Ice Sheet, which covered a large area of North America during glacial periods of the Quaternary.