ACROSS UNKNOWN SOUTH AMERICA 
Some 300 metres down this long straight stretch of 
river a tributary eight metres wide, coming from 210° 
bearings magnetic, threw itself into the Arinos. Strong 
eddies were formed, as many rocks were strewn in the 
centre of the stream. 
One kilometre farther a conglomerate mass of granite 
and yellow and red lava, with impurities embedded in it, 
emerged just above the water in the centre of the stream. 
Another streamlet, two metres wide, and of wonder¬ 
fully limpid water, joined the Arinos on the right side. 
It came from the northeast. Then another little streamlet 
was seen on the left side. 
At the end of 10 kilometres, where the river made a 
wide angle from 330° to 350° bearings magnetic, and an¬ 
other straight line of 4,000 metres stretched in front of us, 
we beheld a huge submerged bank of sharp volcanic con¬ 
glomerate rock. In fact, we unexpectedly almost ran 
into it. Had we done so at the rate at which we were 
travelling, our canoe would certainly have been smashed 
to pieces against the sharp-edged fractured rock, just as 
sharp at the angles as the blades of knives. 
Where the river turned once more from 350° to 320° 
bearings magnetic another small tributary appeared on 
the right bank, and there a lot of handsome mate trees 
(Ilex paraguayensis) seemed to flourish, and were cer¬ 
tainly pretty to look at. 
Farther down we again came to chapada on the left 
bank and heavy-foliaged forest with a certain number 
of rubber trees on the right bank. The left bank, where 
it described a great sweeping circle, was low and sandy, 
some twelve feet above the level of the river. Only a thin 
fringe of low trees grew there on the edge of the water. 
Six kilometres from the last tributary on the right 
bank another streamlet, three metres wide, coming from 
the south-southwest, cut its way through the left bank. 
Two thousand five hundred metres farther on another 
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