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SOUTH AMERICA.
It will be observed that tho contimmt of South .A.merica has a general triangnlal'
shape. In the north a mountain system runs east and west; again we find the ame
thing farther south in Brazil. In thewest is tho great chain of the Audes traversing
the entire continent from north to south. Leaving Patagonia, they enter Chili, rising
higher and bigher, nntil they culminate in the volcano Aconcagua. At the uouudary
ofBolivia, the chain turns to the northwest and separates iuto two, inclosing the table–
land ofthe Desaguadero, a wouderful valley, haviug at one end Potosi, the highest city
in the world, and at the other Cuzco; between them is Lake
Ti
ticaca, from which not
a drop of water escapes except by evaporation. At Paseo a third cordillera is throwu
off, aud with a triple arrangement and alower altitude the Andes enter the Republic
ofEcuauor, where the double line is resumed. Just above the equator one rídge is
formed which then spreads out like a fan; one cordillera goes to the east, giving rise
on its easte..-n slopes to the Orinoco ancl its tributarios, the central cordillera having
the volcano ofTolima, soonloses itself in the Carribbean
~ea,
and the western turning
to the left, with a much lower altitude traverses the isthmus, rises
in
altitude, and
expands again to form the table-land of Mexico. The snow limit at the equator is
15,800
feet; at 27 degrees it is
13,800
feet, and at
33
degrees it is
12,780
feet. Twenty–
two of the fifty-one volcanoes in tbe Andes have their summits covered with per–
petua} snow, and twenty encircle the valley of Quito.
The Andes almost stop tbe trade-winds (which are again felt at
150
mile from the
coast), causing them to drop their moisture on the castern slopes, and thus give rise to
tbose great rivers, the Orinoco, the Amazon, ancl the La Plata, whicb, flowing east–
ward, almosti quarter the coutinent.
Near Cerro de Paseo in a Iiate lake, just below the 1imit ofperpetual snow, and
scarcely 60 miles from the Paci.fic rises the greate t river in tbe world. Flowing
northerly
500
miles through adcep valley, it turus on reaching the frontier of Ecuador
to the right anu runs easterly
2,500
miles. At Tabatinga,
2,000
miles from its mouth,
it is a mile and a half wide. So many and far-reaching are its tribntaries that it
touches every country of the continentexcept Chili and Patagonia. These tribu t::u·ies
communicate with each other by so many intersecting canals that Central Amazonia
is a cluster of islands, and ifa circle be drawn
1,600
miles in d1ameter it will inelude
an ever green unbroken forest.
The Amazon really líes in a plain, for the slope from the month ofthe Napo to the
ocean, in a direct line
1,800
miles, is bnt
1
foot in 5 miles. A fair conception of tbis
will be obtained from an examiuation of the altitudes on the edges of this p1ain,
bounded
by
the grassy plains of Venezuela, the chain of tbe Andes, and the table landa
of :Matto Grosso.
The Cassiquiare, a natural canal three-fourths of a mile wide, and with a pQrtage
of only two honra, connects the headwaters of the Orinoco and tbe Amazon.
Of
the tributaríes of tbe Amazon, the Putumayo and the Napo ri e among the moun–
tains of Colombia and Peru. The Pastassa rises
in
the valley of Quito and trav–
ersas a very steep course; the M:aranon, or the main river, rises near Cerro de Paseo.
The Hnallaga comes from the Pernviau Andes at an elevation of 8,600
feet~
and is
naviga.ble for steamers to the port of Moyobmnba. Its mouth is amile wide. Canoe
120