THE RAPIDS OF THE MADEIRA AND THE MAMORE. 
(iS 
the highest flood-level ; Avliile the hills, seen at a little distance to the | 
^ left, attain a height of 330 feet above the base. 
Tlie right hank is comparatively flatter; yet here and there are , 
' visible the tops of distant hills. 1 
^ flhe next rapid, Do Paredao, is caused by a cliff of coarse-grained ! 
^ granite projecting into the river for more than 330 feet. On its j 
uttermost extremity arc some blocks of the same material, bordering a ' 
^ deeply-worn channel, whose smooth vertical walls have given it the name ] 
of' Paredao — that is, supporting wall. The slope is of nearly 0^ feet. i 
Of about the same height is the next rapid of Pederneira (fliutstono), 
«s. where veins of quartz appear on the smface, and the whole course of 
fPo stream is strevTi with isolated blocks of various size. At both 
these rapids the cargo only need be transported on land, the canoes 
•V being tracked in the river. 
Above Pederneira the Madeira is perfectly free of obstructions. 
Folio vdng its former course from South-west to North-east, up to the 
y mouth of the Abuna, it foms at Pederneira a shai-p bend almost 
.V, rectangular in its deviation. 
From time to time, wavy, and in some parts perfectly horizontab 
> strata of a ferruginous slaty sediment resembling sandstone appear 
on the banks, which rise to a height of between 50 and 60 feet 
above low- water level. The chain of hills on the left side, which at 
Poderneii’a came close to the water’s edge, now disappears from view; I 
ti’ as far as the eye can reach, extend densely wooded plains, never 
^ visited by the white man. The breadth of the river here is nearly i 
1,100 yai-ds, while the depth averages from 16 to 20 feet, and the I 
^ declivity is less than 1-30,000; so that, for nearly 37 miles, the river 
is navigable by the largest vessels and steamers. 
^ The point farthest west of the Madeira River we found to be 
3,280 yards above the mouth of the Abima influent, which has hitherto 1 
^ enjoyed that designation. Here the river again changes its direction, | 
^ describing from Araras, the next rapid, a great curve to the Abima, 
^ and thus forming a sort of peninsula between this point and Paredao. ; 
^ A second horde of Caripunas have chosen this spot for their settle- ' 
ment, evidently for the same reason that induced their relations to 
^ build their sheds on the smooth below the Caldeirao do Inferno— the I 
stream, which is free of obsti-uction, afi'ording them easy commimication, ' 
' and thus facilitating their hunting and fishing exem-sious. Some old I 
