Page:Oregon Historical Quarterly vol. 9.djvu/300

276 Above these obstructions the Columbia with its tributaries is navigable to the extent of 1,294 miles. Thus the Columbia would be navigable for 1,664 miles were it not for these obstructions.

The Cascade range of mountains extends entirely across the States of Oregon and Washington, and the only natural opening in the range is the Columbia River. Through this opening is the natural transportation route for the products of the great valley of the Columbia to the seaboard and of the supplies for the inhabitants of that region. The Columbia River is in size and importance the second in the United States. The total area drained by it is 244,959 square miles. It is divided as follows: