At 10,497 feet (3,199m), Mount Jefferson is the second tallest mountain in Oregon. It is a stratovolcano with slopes mantled by five glaciers - Whitewater, Waldo, Milk Creek, Russell, and Jefferson Park. Three Fingered Jack is a heavily eroded and deeply glaciatedshield volcano and consists mainly of basaltic andesite lava.[5] At 7,841 feet (2,390m), it is made up of the solidified lava plug flanked by ridges of the old volcano's subsidiary lava dikes and lies at the southern end of the Mount Jefferson Wilderness.[4] Other geographic features of the wilderness include steep talus slopes, rock outcrops, and alpine meadows.[6]
Several lakes are situated within the wilderness area, including Marion Lake, Duffy Lake, Santiam Lake and Wasco Lake. Between Three Fingered Jack and the North Sister volcano and among recently active basalt lava fields, there is an array of cinder cones encompassing an area of 85 square miles (220km2).[7]
Common wildlife found in Mount Jefferson Wilderness include deer, black bear, coyotes, and bald eagles.[4] The Wilderness also includes Marion Lake, which is a breeding location for amphibians such as the rough-skinned newt.[8] Roughly half the lakes in the Mount Jefferson Wilderness area contain rainbow trout.[9]
Recreation
Common recreational activities in Mount Jefferson Wilderness include hiking, backpacking, camping, cross-country skiing, wildlife watching, and mountain climbing on Mount Jefferson and Three Fingered Jack. There are some 190 miles (310km) of trails in the wilderness, including a 40-mile (64km) stretch of the Pacific Crest Trail.[6]