The rivers which rise on the eastern side of the Appalachian range run
into the Atlantic; those which rise west of the Rocky Mountains empty
themselves into the Pacific; while the mighty streams which flow between
the two, pass through the great basin of the Mississippi, and swell the
waters of that mother of rivers. The great valley of the Mississippi,
indeed, drains a surface greater than that of any other river on the
globe, with the exception perhaps of the Amazon. The Missouri, even
before it reaches it, runs a course of 1300 miles, while the Mississippi
itself, before its confluence with the Missouri, has already passed over
a distance of 1200 miles; thence to its mouth its course is upwards of
1200 miles more. The Arkansas, which flows into it, is 2000 miles long,
and the Red River of the south 1500 miles in length; while the Ohio, to
its junction with the Mississippi, is nearly 1000 miles long.
North America may be said to contain four great valleys--that of the
Mississippi, running north and south; that of the Saint Lawrence, from
the south-west to the north-east; that of the Saskatchewan, extending
from the Rocky Mountains below Mount Brown to Lake Superior; that of the
Mackenzie, from the Great Slave Lake to the Arctic Ocean. Although a
large portion of the eastern side of the continent is densely-wooded,
there are towards the west, extending from the Gulf of Mexico to the
Arctic Ocean, vast plains. In the south they are treeless and barren in
the extreme; while advancing northward they are covered with rich
grasses, which afford support to vast herds of buffaloes, as well as
deer and other animals.