the wells gray-clearwater volcanic field in southeastern british columbia consists of numerous small, basaltic volcanoes and extensive lava flows. many individual volcanoes in the field have been active for the last 3 million years during which time the region was covered by thick glacial ice at least twice, prior to the well known fraser glaciation (also known as the wisconsin glaciation). the origin of the volcanism is yet unknown but is probably related to crustal thinning. the last eruption in the field was at kostal cone in 1500. volcanism within the field has also created the -high helmcken falls, which is the fourth highest waterfall in canada. it owes its foundation to the deposits of volcanic rock that were placed down in the wide valley of the murtle river. layer upon layer of fresh lava created flat areas, over which enormous floods flowed during the last ice age. these floods shaped the upright cliff in the lava flows over which the river now flows. the protection of helmcken falls was one of the major causes for the development of wells gray provincial park. as a result, if it had not been for the volcanic eruptions, it is not likely that such a large wilderness region would have been made.