NOTES OF A BOTANIST 
had, in fact, got there a few days before us, and we 
were glad to rest with him through the 7th and 
part of the 8th, and to compare our experiences of 
travel since we parted. Here, too, we gave up to 
him his boat, and got the loan of a smaller one and 
of a couple of stout Indians, and a boy to steer, for 
the short remainder of the voyage. We had four 
rocky points to pass before reaching the mouth of 
the Rio Negro, the first and worst being called 
Puraqu6-coara (Electrical Eel's hole), and like the 
rest consisting of stratified arenaceous rock of a 
purplish grey colour, less granular than the Para 
grit. 
We entered the mouth of the Rio Negro on the 
morning of December the loth. At the junction 
with the Amazon a bar of reddish friable rock 
stretches out a long way ; when the rivers are full 
there is deep water over it, but we found it still 
uncovered, and had some difficulty in hauling our 
canoe through the furious current at its extremity. 
On a steep hill rising from the water's edge stood 
formerly the Fortaleza da Barra, built to command 
the entrance to the Rio Negro, but overthrown by 
the Cabanos in 1835. The city of the Barra, how- 
ever, or Manaos, as it is now called, stands some 
eight miles within the Rio Negro. 
The change from the yellow water of the Amazon 
to the black water of the Rio Negro is very per- 
ceptible, and indeed abrupt. The latter is black as 
ink when viewed from above, and stones or sticks 
at the bottom seem red ; but when taken up into a 
glass it is of a pale amber colour, and quite free 
from any admixture of mud. 
The Rio Negro is broader than the Solimoes — 
