At least three phases of eruptive activity have been identified at Mount Price. The first event 1.2 million years ago deposited hornblende andesite lava and pyroclastic rocks on the floor of a cirque-like basin after an Early Pleistocene glacial event. The Black Tusk, a deeply dissected stratovolcano north of Mount Price, was also active during this period. Because older volcanic events have not been identified in the Garibaldi area, this is the oldest known eruptive period in the Garibaldi Lake volcanic field.