t of June
6th--7th. There was a thick haze over the river in the morning, and as we
did not know what we might be coming upon suddenly we did not make a
start until 7.15. After crossing a large and shallow bay the stream was
forced into a channel 50 m. wide. There was open country--campos--on the
right bank. A curious isolated volcanic boulder split in two was then
observed in the stream, while the banks were of alluvially deposited
conglomerate. From that spot luxuriant forest was on the right bank once
more, while open country was on the left. Upon examination I found that
the thick forest was merely a band or zone near the water--behind was
open country.

Farther, the river went through a neck 40 m. wide where the current was
very swift. The banks almost all along were from 10 to 20 ft. high.
Slender _tucuma_ or _tucuman_ palms were to be seen, which had stems only
3 to 4 in. in diameter, but were 30 to 40 ft. high, and had a ball-like
tuft of leaves at the top. We then came upon open country (_chapada_) on
both sides, and went over small _corrideiras_, which we got to like, as
we travelled along on them at a greater speed than in the still waters,
with a minimum of exertion. The river seemed to be getting narrower all
the time that day, and, of course, deeper. In many spots it went through
a channel not more than 30 m. wide.

We heard--but not for long--the cackling of the _jacu_ (_Penelope
cristata_), a handsome gallinaceous bird. The _jacu_ made most delicious
eating. Then that day flocks of small green parrots flew over our heads
on several occasions.

_Ariranhas_ gave us once more a good deal of amusement and sport. It was
seldom one found such cheeky and inquisitive animals. They would pop
their heads out of the water quite close to the canoe and sniff and grind
their teeth at us. They had beautiful little heads--something between a
cat and a seal--with lovely, but wicked, black eyes of wonderful
luminosity. They had a perfect craving for blood. The Brazilians have
strange tales about them--not exactly fit for publication.

The sand beaches were not so frequent as we advanced on our journey. We
noticed instead extensive beaches of gravel. Another tributary stream, 10
m. wide at its mouth, entered the Arinos from the east. There was heavy
forest there with plenty of rubber-trees on the right bank, whereas the
country was open on the left bank.

Farther down, the banks became low, so that the slightest rise