rked back. But it came
not from a dog at all. The peculiar noise was made by a large bird.

[Illustration: A Rocky Barrier in the River.]

[Illustration: A Picturesque Double Waterfall on the Arinos River.]

After passing a handsome beach of white sand on our left, the river
described sharp angles, west, north-west, north-east, then north. There
were rapids, fairly strong, although not dangerous in any way. The river
was forced through a channel 50 m. wide, in which the current was very
strong. To make things worse, a giant tree had fallen and obstructed much
of the passage, compelling us to negotiate the rapid in its worst part. A
large bay, 180 m. in diameter, opened out below that point. Farther came
a perfectly straight stretch of water for 3,000 m. Halfway down that
stretch, to the right, we passed the mouth of the Agua Clara, a charming
rivulet of crystalline water, 10 m. wide. A conglomerate stratum of
alluvial formation, composed of well-rounded pebbles held together by red
earth, and crumbling easily under pressure of the fingers, showed through
in many places. The beaches of handsome, fine white sand were most
interesting.

The forest was getting thin on both sides. In fact, late in the afternoon
we had open country on the left bank--only a few trees being visible near
the water's edge, and an occasional giant _jatoba_ (_Hymencoea Courbaril_
L.), the latter chiefly on the right bank. The right bank was sparsely
wooded, and at one time we had open campos on both sides of us.

A streamlet 3 m. wide entered the Arinos on the left. We got to one point
where the river proved treacherous, although apparently almost tranquil
on the surface. The Brazilians have an excellent name for such
places--_rebojo_, or a curve formed by sudden deviation of a current. If
we had not been careful in going across such places, it would have been
easy for the canoe to have been turned over and sucked under.

Patches of thick forest were met on either bank, and in those patches
numerous indeed were the rubber trees. In the afternoon we saw chiefly
campos and _chapada_, or thin scrub.

Considering all, we did well--chiefly owing to the strong current--on our
first day of navigation. We had gone some 70 kils. when we halted at
sunset, at the junction of the very deep streamlet Quarustera with the
Arinos. The elevation of our camp, 60 ft. above the river, was 1,200 ft.

The nights were cool enough--minimum 55 deg. Fahr. on the nigh