ACROSS UNKNOWN SOUTH AMERICA 
mense basin, 1,000 to 1,500 metres broad from west to 
east, interspersed with elongated, rounded, and flattened 
rocks. It was indeed a most picturesque sight, especially 
when all the trading boats were winding their way at 
sunset, descending the various rapids. 
After going through a great channel, we went along 
a large fissure from southeast to northwest, still in the 
Mangabel rapid. The rock of that region was highly 
ferruginous. That fissure was of great depth, and the 
channel itself was absolutely free from rocks. 
When we emerged from the fissure we were confronted 
to the east on the right bank by two enormous hemi¬ 
spherical domes, 100 feet high, grassy but absolutely 
without a tree. 
The rocky formation of the hills was apparent a 
little farther down stream, when going along the great 
eastern channel of the river. On the left bank we had 
hills with campos on their summit. All the hills I noticed 
in that region had rounded backs. 
I greatly admired the bearing of Colonel Brazil as 
we dashed down at a terrific speed through the most 
intricate channel in the rapid, strewn with sharp rocks. 
Had we touched one of those rocks it would have meant 
the destruction of the boat, the loss of all the valuable 
cargo and most of the crew, as the majority of them could 
not swim. 
There were three passages there, called respectively 
the Casson, near the left bank; the Dos Ananas, in the 
centre; and the channel da Terra Preta, which we fol¬ 
lowed, on the right. At Lua Nova, the end of the Man¬ 
gabel rapid, the river turned in a sweeping curve to the 
north, the rocks becoming fewer and fewer until eventu¬ 
ally the river became quite clear of them, with only high 
hills along both banks. Lua Nova was a little settlement 
of five houses and a shed, some of them whitewashed, with 
doors and windows painted green. A small plantation 
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