170 
THE UPPER AMAZONS. 
Chap. III. 
afterwards learnt that there were not more than 
eighteen or twenty families settled throughout the 
whole country from Manacapuru to Quary, a distance 
of 240 miles ; and these, as before observed, do not 
live on the banks of the main stream, but on the 
shores of inlets and lakes. 
The fishermen twice brought me small rounded pieces 
of very porous pumice-stone, which they had picked up 
floating on the surface of the main current of the river. 
They were to me objects of great curiosity as being 
messengers from the distant volcanoes of the Andes : 
Cotopaxi, Llanganete, or Sangay, which rear their peaks 
amongst the rivulets that feed some of the early tribu- 
taries of the Amazons, such as the Macas, the Pastaza, 
and the Napo. The stones must have already travelled 
a distance of 1200 miles. I afterwards found them 
rather common : the Brazilians use them for cleaning 
rust from their guns, and firmly believe them to be 
solidified river foam. A friend once brought me, when 
I lived at Santarem, a large piece which had been found 
in the middle of the stream below Monte Alegre, about 
900 miles further down the river : having reached this 
distance, pumice-stones would be pretty sure of being 
carried out to sea, and floated thence with the north- 
westerly Atlantic current to shores many thousand miles 
distant from the volcanoes which ejected them. They 
are sometimes found stranded on the banks in different 
parts of the river. Reflecting on this circumstance since 
I arrived in England, the probability of these porous 
fragments serving as vehicles for the transportation of 
seeds of plants, eggs of insects, spawn of fresh-water 
