onora
Island.

The north-eastern passage was shallow, with a stony bottom. We followed
the northern channel along the vertical wall. On leaving the island we
came to a stretch 2,500 m. long of beautiful water flowing due north,
with ideally fascinating banks embellished by dense vegetation--neat,
clean, and healthy--of the richest green.

After crossing a bay, 100 m. wide, with volcanic rocks showing through on
both banks and in the river bed, the stream was squeezed through a rocky
neck 25 m. wide, and spread again immediately afterwards to its normal
width of 50 m. We were beginning to find big rocks more frequently, many
in the river channel--a bad sign for us, for I feared we might soon
encounter rapids.

Wonderful _oleo pardo_ trees (_Myrocarpus frondosus_ Fr. All.), with
their octopus-like branches hanging down to the water, were fairly common
in that region. There were two kinds of _oleo_ trees in Brazil--the brown
or _oleo pardo_ and the red or _oleo vermelho_, the latter technically
known as _Myrospermum erytroxylon_ Fr. All.

We subsequently entered a basin 150 m. wide which contained a circular
island 100 m. in diameter--Horus Island.

Eight hundred metres farther we came to another large circular bay with a
large globular mass of lava on its left side. The current was very swift
over a nasty rocky bottom. The canoe was suddenly flung by the current
between an accumulation of rocks and an island, and, as we found it
impossible to turn, floated down at an uncomfortable speed through a
narrow channel, dodging as best we could the many ugly rocks just below
the surface of the water. At the end of this channel we encountered
violent eddies forming wide circles of most treacherous water--although
on the surface it looked placid enough.

The tributary Sumidoro, 30 m. wide at its mouth, entered the Arinos from
the west-south-west at this point. Its water was deliciously clear. A
little way off to the left we could hear the noise of a waterfall on the
Sumidoro, before it joined the Arinos.

The river, after the meeting of this important tributary, became even
more exquisitely beautiful than before. Rocks strewn about added to the
picturesqueness of the landscape as well as to the dangers of navigation,
while springs of crystalline water, cool and quite delicious to drink,
descended here and there from the banks.

The river had an average width of 60 m. in this part, and was much strewn
with broken-up volcan