"The course and elevation of these ranges give direction to the rivers, and character to the coast. No great river does, or can, take its rise below the Cascade and Sierra Nevada Range; the distance to the sea is too short to admit of it. The rivers of the San Francisco Bay, which are the largest after the Columbia, are local to that bay, and lateral to the coast, having their sources about on a line with the Dalles of the Columbia, and running each in a valley of its own, between the Coast Range and the Cascade and Sierra Nevada Range. The Columbia is the only river which traverses the whole breadth of the country, breaking through all the ranges, and entering the sea. Drawing its waters from a section of ten degrees of latitude in the Rocky Mountains, which are collected into one stream by three main forks (Lewis's, Clark's, and the North Fork), near the centre of the Oregon valley, this great river thence proceeds by a single channel to the sea, while its three forks lead each to a pass in the mountains, which opens the way into the interior of the continent. This fact in relation to the rivers of this region gives an immense value to the Columbia. Its mouth is the only inlet and outlet to and from the sea; its three forks lead to the passes in the mountains; it is, therefore, the only line of communication between the Pacific and the interior of North America; and all operations of war or commerce, of national or social intercourse, must be conducted upon it. This gives it a value beyond estimation, and would involve irreparable injury if lost. In this unity and concentration of its waters, the Pacific side of our continent differs entirely from the Atlantic side, where the waters of the Alleghany Mountains are dispersed into many rivers, having their different entrances into the sea, and opening many lines of communication with the interior." "The Pacific coast is equally different from that of the Atlantic. The coast of the Atlantic is low and open, indented with numerous bays, sounds, and river estuaries, accessible everywhere, and opening by many channels into the heart of the country. The Pacific coast, on the contrary, is high and compact, with few bays, and but one that opens into the heart of the country. The immediate coast is what the seamen call _iron bound_. A little within, it is skirted by two successive ranges of mountains, standing as ramparts between the sea and the interior country; and to get through which, there is but one gate, and that narrow and easily defended. This structure of the coast, backed by these two ranges of mountains, with its concentration and unity of waters, gives to the country an immense military strength, and will probably render Oregon the most impregnable country in the world."