ACROSS UNKNOWN SOUTH AMERICA 
beautiful bamboos interspersed with gigantic palms lined 
the banks. 
Where the river turned due east we came to fairly 
strong rapids. The water was shallow with mounds of 
gravel, and we bumped about a great deal. Eventually 
we all had to get into the water and push the canoe along 
for greater comfort. 
The river next formed a huge basin, 900 metres long 
and 200 metres wide. A small tributary flowed into the 
Arinos in the crescent-shaped bank on the right. That 
bank had a height of eighty feet. On its summit quantities 
of Siphonia elastica were to be admired. Farther down 
it was on the left side that the river had high banks, some 
sixty feet high. 
We went over a charming little corrideira. Strong 
eddies were encountered on emerging from the rapids. 
Where the right bank became lower — only forty feet — 
chapada replaced the forest. The left bank was but one 
foot above the level of the river, and the low country 
beyond (south) was naturally liable to inundation. For 
4,000 metres the left bank was never higher than four 
feet. The right bank also suddenly became very low in 
that region. 
Where the river turned from 290° bearings magnetic 
to 320° bearings magnetic, there was a basin 700 metres 
broad with low banks. Lydia Island, 200 metres in cir¬ 
cumference, rose within this basin on the north side and 
was luxuriantly wooded. 
We found that day beautiful beaches of gravel, mostly 
on the right side. Then strong rapids and corrideiras; 
below these more clean-looking gravel beaches, this time 
on the left, were visible, and an extensive island of gravel 
close to the right bank. 
For 8,000 metres the gorgeous stream flowed almost 
in a direct line northward, with dense forest and a wealthy 
growth of rubber trees on both sides. Wonderful figueira 
52 
