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."

"Differing so much from the Atlantic side of our continent in coast,
mountains, and rivers, the Pacific side differs from it in another
most rare and singular feature--that of the Great interior Basin,
of which I have so often spoken, and the whole form and character of
which I was so anxious to ascertain. Its existence is vouched for by
such of the American traders and hunters as have some knowledge of
that region; the structure of the Sierra Nevada range of mountains
requires it to be there; and my own observations confirm it. Mr.
Joseph Walker, who is so well acquainted in those parts, informed
that, from the Great Salt Lake west, there was a succession of lakes
and rivers which have no outlet to the sea, nor any connection with
the Columbia, or with the Colorado of the Gulf of California. He
described some of these lakes as being large, w