This immense territory is far from being a
vast level plain. On the extreme east is the Great Plains region of
the Mississippi Valley which is a comparatively uniform country of
rolling hills, but no mountains. At a point about one third of the
whole distance westward the whole land is lifted skyward by the
Rocky Mountains, which cross the country from south to northwest.
Here are innumerable peaks, canons, high table-lands, roaring
torrents, and quiet mountain valleys. West of the Rockies is the
great depression known as the Great Basin, which has no outlet to
the ocean. It is essentially a gigantic level lake floor traversed
in many directions by mountain ranges that are offshoots from the
backbone of the Rockies. South of the Great Basin are the high
plateaus, into which many great chasms are cut, the best known and
largest of which is the great Canon of the Colorado. North and east
of the Great Basin is the Columbia River Basin characterized by
basaltic rolling plains and broken mountain country. To the west,
the floor of the Great Basin is lifted up into the region of eternal
snow by the Sierra Nevada Mountains, which north of Nevada are known
as the Cascades.
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