In that part of the basin of the Orinoco
which runs in the direction of from south to north, as well as in that
running from west to east, the maxima of depression are found at the
foot of the Sierra Parime, we may even say, on its outline.
4. THE BASIN OF THE RIO NEGRO AND THE AMAZON.
This is the central and largest basin of South America. It is exposed
to frequent equatorial rains, and the hot and humid climate develops a
force of vegetation to which nothing in the two continents can be
compared. The central basin, bounded on the north by the Parime group,
and on the south by the mountains of Brazil, is entirely covered by
thick forests, while the two basins at the extremities of the
continent (the Llanos of Venezuela and the Lower Orinoco, and the
Pampas of Buenos Ayres or the Rio de la Plata) are savannahs or
prairies, plains without trees and covered with gramina. This
symmetric distribution of savannahs bounded by impenetrable forests,
must be connected with physical revolutions which have operated
simultaneously over great surfaces.
(4a.) PART OF THE BASIN OF THE AMAZON, RUNNING FROM EAST TO WEST,
BETWEEN 2 DEGREES NORTH AND 12 DEGREES SOUTH; 880 LEAGUES IN LENGTH.
The western shore of this basin is formed by the chain of the Andes,
from the knot of the mountains of Huanuco to the sources of the
Magdalena. It is enlarged by the spurs of the Rio Beni,* (* The real
name of this great river, respecting the course of which geographers
have been so long divided, is Uchaparu, probably water (para) of Ucha;
Peni also signifies river or water; for the language of the Maypures
has very many analogies with that of the Moxos; and veni (oueni)
signifies water in Maypure, as una in Moxo. Perhaps the river retained
the name of Maypure, after the Indians who spoke that language had
emigrated northward in the direction of the banks of the Orinoco.)
rich in gem-salt, and composed of several ranges of hills (latitude 8
degrees 11 minutes south) which advance into the plains on the eastern
bank of the Paro. These hills are transformed on our maps into Upper
Cordilleras and Andes of Cuchao. Towards the north the basin of the
Amazon, of which the area (244,000 square leagues) is only one-sixth
less than the area of all Europe, rises in a gentle slope towards the
Sierra Parime. At 68 degrees of west longitude the elevated part of
this Sierra terminates at 3 1/2 degrees north latitude. The group of
little mountains surrounding the source of the Rio Negro, the Inirida
and the Xie (latitude 2 degrees) the scattered rocks between the
Atabapo and the Cassiquiare, appear like groups of islands and rocks
in the middle of the plain.
