OBSTACLES IN THE RIVER 
into two arms, one northwest, 25 metres wide; the other 
northeast, 30 metres broad. The island thus formed be¬ 
tween the two arms was 2,500 metres long. We called 
it Ariranha Island. 
A streamlet three metres wide entered the Arinos on 
the right bank. Where the banks were free from vege¬ 
tation an undulating stratum of red earth was exposed, 
directly above which was a stratum from one to two feet 
thick of a brilliant yellow colour. Above that rested the 
usual grey alluvial deposits from six to eight feet thick. 
From a direction due west the stream suddenly turned 
north, between high banks. A strong corrideira was 
found before the stream divided itself into three arms, two 
of those arms flowing northeast, the other northwest. We 
followed the latter, a channel 20 metres wide, with a high 
bank of gravel on its left side. Where those arms met 
again, some 500 metres farther, a basin 200 metres in 
diameter was formed. A hill 150 feet high, covered with 
dense vegetation, faced us to the north. It was quite an 
unusual sight in such flat country. The stream took a 
sharp turn at that spot — it positively doubled. Strong 
eddies were encountered. The greatest care should have 
been taken in going over places of that kind, but “ care ” 
was a word I had scratched out of my vocabulary as 
absolutely useless in my journey across Brazil. How and 
why we ever got across those places with the crew I had 
on board, would indeed be beyond me to explain, unless, 
as on preceding occasions, it was due to the unceasing 
protection of a guardian angel. 
After crossing a circular basin 200 metres in diameter, 
the river became suddenly squeezed into a channel 30 
metres wide, much strewn with rocks. A somewhat 
troublesome rapid had to be negotiated there, rendered 
more difficult by the recent fall, across the best part of 
the stream, of a giant tree. The branches which stuck 
out of the water formed a regular barrier and waved to 
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