Cascade Range, a chain of mountains of North America in Oregon and Washington State, U.S., and in British Columbia. It takes its name from the great cascades of the river Columbia, which are situated at the point where that stream cañons through the range by a pass 4000 feet deep. The course of the mountain-chain in the United States is from north to south nearly parallel to the Pacific coast-line, and from about 110 to 160 miles distant from it. Southward it is continuous with the Sierra Nevada of California; northward it connects with the unsurveyed range which forms the boundary between British Columbia and Alaska.
The chain throughout most of its course is heavily wooded, chiefly with evergreen conifers, including pines of various species, firs, spruces, cedars, and trees locally known as cypress, larch, juniper, and yew. Southward there is some alder, ash, and maple, and even a little oak. The presence of beautiful cone-shaped and perpetually snow-clad peaks is a most striking feature. There are quite a number of rather low transverse passes which may, in time, become important highways. Near the south end of the range stands Mount Pitt (9818 feet high). Forty miles north is Mount Scott (9016 feet), a mere fragment of a now extinct volcano of enormous dimensions. Its western walls are almost perpendicular. Forty miles still northward, after passing many wonderful old volcanoes and lava-beds, we come to Diamond Peak (8807 feet), which is also the remnant of an old crater-rim. The Three Sisters (9000 feet) are of similar character. Mount Jefferson is 10,200 feet high, and Mount Hood 11,225 feet. The principal peaks in Washington are Mounts Baker (10,700 feet), Tacoma or Rainier (14,444 feet; in eruption in 1894), and St Helen's (12,000 feet). In this region volcanic action is not extinct. In British Columbia the range comes much nearer the sea-coast.
The Cascade Mountains, with the Sierra Nevada, are much more recent geologically than are the Rocky Mountains proper. They were probably formed about the close of the Jurassic period, although the now visible volcanic products seen along the range are of much later, and even quite recent, date; the earliest volcanic fissures being referable to the end of the Miocene period, at which time, or a little earlier, the parallel Coast Range began to be raised.