TOPOGRAPHY. Washington closely resembles Oregon in its main topographical features, and, as in Oregon, the Cascade Mountains divide the State into a smaller western and a larger eastern section, which are strongly contrasting in their climatic and other characteristics. The Cascade Mountains form a lofty plateau falling steeply on both sides, and eroded into a rugged complex of peaks and ridges nearly 100 miles wide. The main crest has an average altitude of about 5000 feet, but from the southern part of the plateau the three great volcanic cones of Mount Rainier ( Mount Tacoma ), which bears a numl)er of glaci ers, Mount Adams, and Mount. Saint Ilelens rise, respectively, to altitudes of 14,520, 12,470, and 10, 000 feet. In the northern part of the range the highest point is Mount Baker, with an altitude of 10,827 feet. Front the eastern base of the Cascades and south of the Great Bend of the Columbia stretches the vast basaltic plateau, an undulating, treeless plain lying between 1000 and 2000 feet above the sea. Almost the only irregu larities in its surface are the cafion-like valleys of the Columbia and its branches, and the coniees, more or less dry canons, which indicate the for mer paths of the river. West of the Columbia, however, the lava field has been upturned in a series of monoclinal ridges running east and west as spurs of the Cascades, and south of the Snake River, in the southeastern corner of the State, there is another uplift, known as the Blue Mountains, exceeding 5000 feet in altitude. The northeastern quarter of the State, north of the Great Bend and the Spokane River, is rugged and mountainous, forming part of the Moun tain system, and rising in some of its peaks to an altitude of over 0000 feet. The central feature of western Washington is the Puget Sound Basin, a longitudinal depression between the Cascade and Coast corresponding to the Willamette Valley of Oregon. Its highest parts are scarcely
Over 100 feet above the sea, and it is penetrated through more than half its length by the nuiner ous branching arms of Puget Sound, form ing one of the most magnificent systems of har bors in the world. The Coast Range is not very pronounced in the south, consisting of broad ir regular masses seacelw• exceeding 2000 feet in altitude. In the north, however, it rises into a well-defined group called the Olympie Moult thins, whose highest point is Mount Olympus, with a height of 8150 feet. The Pacific coast itself is straight and regular, practically the sole being Gray's and 'Willapa harbors.
11ThnonnAmtv. The only large independent river in Washington is the Columbia, which drains the entire eastern section of the State. It enters the State near its northeastern corner and flows through the northern mountains and the lava plateau in a southwestward course with a hirge, winding bend. After turning finally it forms the southern boundary of the State Un til it enters the ocean. It would be navigable throughout its course within the State were it not interrupted at frequent intervals by rapids. Its principal tributaries within the linlits of Washington are the Pend Oreille and the Spokane rivers in the northeast and the Snake River in the southeast. Its chief affluent from the east slope of the Cascades is the Yakima. Western Washington is drained by a large number of comparatively small streams flowing into Puget Sound and the ocean. The largest of those entering the sound are the Skagit in the north and the Nesqually in the south. Of the streams rising on the western slope of the Cascades only one, the Chehalis, breaks through the Coast Range and enters the ocean di rectly. There are a number of lakes in eastern Washington, but most of them are either ex panded rivers, such as the long and narrow Lake Chelan, the largest in the State, o• remnants of old river courses.