“ The name, however, is commonly assigned to the entire plateau region stretching across the province from southeast to northwest, which is limited on the east by the lofty ranges of the Rocky Mountains, and on the west by the Island Range. The southern section of the range is crossed by the Columbia River and by the Klamath River, both of which have cut deep gorges. In British Columbia the Fraser River occupies an extensive cañon, where it passes across the range to discharge into the Strait of Georgia. ”

“ It begins in Northern California near the Oregon boundary and extends across the latter State and Washington into British Columbia, where the line of elevations is continued by many small groups which are deeply intersected and eroded by river and lake systems. Its direction in the United States is nearly north and south, parallel to the Pacific Coast; in Oregon the main axis of elevations lies about 100 miles from the coast, while in Washington the distance increases to 150 miles. ”