d a hill 100 ft. high,
the lower half of which was of red volcanic rock, the upper half of
yellow earth. Along the water's edge a thick and florid growth of bamboo
could be seen in many places, while on the edge of the forest hung
myriads of purple convolvuli. For hundreds of kilometres the Arinos was
indeed one of the most ideally beautiful rivers I have ever seen. Its
banks of alluvial formation, 25 to 30 ft. high, had _chapada_ on their
tops. Farther on the _chapada_ gave way once more to dense forest with
plentiful rubber trees. Another basin, 150 m. in diameter, was met with,
after which we entered a channel from 40 to 50 m. wide, through which the
stream was compressed.

A pretty little islet of gravel, 100 m. long, 20 m. wide, and rising 6
ft. above the water, had a tuft of trees growing on it, and a spur, also
of gravel, extending westward for more than another 100 m. The river in
that section flowed in a W.N.W. direction for 1,400 m.

We soon after came to a shallow basin (1 ft. deep) 100 m. wide, in which
eddies were strong and troublesome. There were many pointed rocks
scattered about in its bed of gravel, as well as three parallel rocky
barriers right across the basin.

A rivulet 2 m. wide at the mouth entered the Arinos on the right side,
while on the left side we had an island 800 m. long, leaving two
channels, one 10 m. wide, the other 40 m. A tiny streamlet flowed into
the main stream on the left. Banks, regular dunes of gravel, were formed
where the river broadened into basins. We came to a basin 400 m. wide and
extremely shallow. Three channels--W.N.W., N.W., and N.N.E.--were formed
in the river by two islands, each 400 m. long--the Two Sisters
Islands--which were in the centre. We found the N.N.E. channel the best.
Where the river narrowed again to a width of 50 m. huge rocks stood in
the centre. From that point for some 300 m. we went over a succession of
gravel banks and nasty rocks forming barriers across the stream.

Small streamlets entered the Arinos, one on the left, the other on the
right. A cluster of high rocks was on the right bank. On both sides were
extensive white sand beaches. The river soon widened to 100 m. in a basin
with an islet 12 ft. high, and a cluster of trees on its north-east side.
Another island 6 ft. high, 80 m. long--Mosquito Island--with a spit of
gravel to the south, was near it.

Rubber trees were most plentiful on the right bank where the forest was
thick, whereas