.

At the end of 10 kil., where the river made a wide angle from 330 deg. b.m.
to 350 deg. b.m., and another straight line of 4,000 m. stretched in front of
us, we beheld a huge submerged bank of sharp volcanic conglomerate 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 deg. b.m. to 320 deg. b.m. another
small tributary appeared on the right bank, and there a lot of handsome
_mate_ trees (_Ilex paraguayensis_) seemed to flourish, and were
certainly 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 12 ft. 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, 3 m. wide, coming from the S.S.W., cut its way through the
left bank. Two thousand five hundred metres farther on another tributary
20 m. wide--a deliciously beautiful stream--flowed gracefully into the
Arinos on the right side from the north-east.

We made our camp at the junction of the two streams. The camp was
extremely bad. It was already late in the evening and we could find no
other suitable spot. We had gone that day 83 kils. I was quite satisfied
with the progress we had made during the last few days. During the
evening I made an excursion on foot along the tributary river to the
north-east for several kilometres, but I found nothing of particular
interest.

During the night we received another visit from an _anta_, but the
pachyderm again escaped before my men had time to kill it. We heard cries
of Indians in the distance. My men were in a great state of mind for fear
we should be attacked. I sat up the entire night in order to be ready in
case of emergency.

I took that opportunity of computing and checking many of the
astronomical observations I had taken, and developing a great number of
photographic glass plates.

In my experience I have found that the fears people have of spoiling
negatives unless one is shut up in an absolutely dark room are quite
exaggerated. On that particular occasion