Physical geography. By Mary Somerville ...

CHAP. XII. VALLEY OF TIE MISISSIPPI. 125
left bank to the Alleghanies is broken into hill and dale, containing
the most fertile territory in the United States. Under so wide a
range of latitude the plain embraces a great variety of soil, climate,
and productions; but, being almost in a state of nature, it is characterized in its middle and southern parts by interminable grassy
savannahs, or prairies, and enormous forests, and in the far north
by deserts which rival those of Siberia in dreariness.
In the south a sandy desert, 400 or 500 miles wide, stretches
along the base of the Rocky Mountains to the 41st degree of N. lat.
The dry plains of Texas and the upper region of the Arkansas have
all the characteristics of Asiatic table-lands; more to the north the
bare treeless steppes on the high grounds of the far west are burned
up in summer, and frozen in winter by biting blasts from the Rocky
Mountains; but the soil improves toward the Mississippi. At its
mouth, indeed, there are marshes which cover 35,000 square miles,
bearing a rank vegetation, and its delta is a labyrinth of streams
and lakes, with dense brushwood. There are also large tracts of
forest and saline ground, especially the Grand Saline between the
rivers Arkansas and Nesuketonga, which is often covered two or
three inches deep with salt like a fall of snow. All the cultivation
on the right bank of the river is along the Gulf of Mexico and in
the adjacent provinces, and is entirely tropical, consisting of sugarcane, cotton, and indigo. The prairies, so characteristic of North
America, then begin.
To the right of the Mississippi these savannahs are sometimes
rolling, but oftener level, and interminable as the ocean, covered
with long rank grass of tender green, blended with flowers chiefly
of the liliaceous kind, which fill the air with their fragrance. In
the southern districts they are sometimes interspersed with groups
of magnolia, tulip, and cotton trees, and in the north with oak and
black walnut. These are rare occurrences, as the prairies may be
traversed for many days without finding a shrub, except on the
banks of the streams, which are beautifully fringed with myrtles,
azaleas, kalmias, andromedas, and rhododendrons. On the wide
plains the only objects to be seen are countless herds of wild horses,
bisons, and deer. The country assumes a more severe aspect in
higher latitudes. It is still capable of producing rye and barley in
the territories of the Assiniboine Indians, and round Lake Winnepeg there are great forests; a low vegetation with grass follows, and
towards the Icy Ocean the land is barren and covered with numerous
lakes.
East of the Mississippi there is a magnificent undulating country
about 300 miles broad, extending 1000 miles from south to north
between that great river and the Alleghany Mountains, mostly covered with trees. When America was discovered, one uninterrupted
forest spread over the country, from the Gulf of St. Lawrence and
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