fragments of great size; then we were once again in a circular basin with
high vertical rocks--perhaps another extinct crater. We were here in a
region of volcanic formation. No sooner had we passed this basin than we
came upon another bad rapid, 400 m. long, which divided itself into two
channels, after going through a narrow passage not more than 30 m. wide,
where we got tossed about in a most alarming manner, being once or twice
nearly dashed to pieces against the rocky sides. We had had so much
trouble with the rapids that day that by sunset we had only gone 19 kil.
600 m. Since we had come to that volcanic region we had found rocks with
great holes in which stagnant water lay. Myriads of insects--regular
clouds of them--worried us nearly to death.

[Illustration: Conveying the Canoe by Hand down a Rapid.]

On August 14th we started early, the minimum temperature having been 70 deg.
F. during the night. After leaving the rapid we came to a great basin
1,000 m. across. A most beautiful sand beach 300 m. long was to be seen
on the left side, below a vertical cliff of great beauty, 200 ft. high.
Another great sand beach was to be seen on the right of the river, where
it described a sharp turn to 30 deg. b.m. Then the river dashed through a
passage of rocks only 80 m. broad, and emerged once more into another
great basin with many indentations in its rocky coast.

Some 6 kil. beyond, another basin was found, with more rocks strewn on
and near its eastern bank, and a number of rocky islets. A high hill
range with vertical cliffs stood on the west side and ended abruptly at
the end of the basin. Low hills ran all along the river on the left side.

The river had an average width here of 250 m., and flowed mostly in
directions between north-west and north-east.

We went down all the time on troubled waters, with rocky banks and
innumerable obstacles all the way. We went through another terrible and
most intricate rapid--the Labyrinth--and passed through a channel only 40
m. wide between high rocky banks. Then, after that, for 9,500 m. we had
fair and smooth navigation, with a range of flat-topped hills 300 ft.
high, extending from W.S.W. to E.N.E., in front of us to the north-west.
Here there was a regular maze of channels, all more or less bad. We did
not follow the principal one, which was strewn with rocks, but a smaller
one, at the end of which, unfortunately, we found a barrier of rocks
which we could not surmount.