Volcanism 22 to 21 million years ago constructed the Coquihalla Volcanic Complex about northeast of Hope. It comprises volcanic and intrusive rocks that are calc-alkaline felsic to intermediate in composition. Coquihalla Mountain, the highest summit of the Bedded Range with an elevation of , is a major preserved stratovolcano and represents one of the few remaining Miocene volcanoes in southwestern British Columbia. As a result, the Coquihalla Volcanic Complex has been a subject of geological studies to annunciate the remains of what might have been an extensive cover of volcanic rocks during the early Miocene epoch. The Coquihalla Complex also has a different igneous composition than Canadian Cascade Arc volcanoes that formed in the last two million years. Rhyolite tuffs are the primary igneous rocks comprising the Coquihalla Volcanic Complex, with small amounts of basalt or andesite present. This contrasts with modern Canadian Cascade volcanoes in that they are mainly composed of volcanic rocks in the basalt to andesite composition range, with few rocks of more felsic composition than dacite. Changes in magma composition have also occurred in the American portion of the Cascade Arc.