264 UPPER AMAZONS—VOYAGE TO EGA. Cuap. X. 
Amazons. ‘They may have been originally cast on the land and after- 
wards carried to the river by freshets ; in which case the eggs and seeds 
of land insects and plants might be accidentally introduced, and safely 
enclosed with particles of earth in the cavities. As the speed of the 
current in the rainy season has been observed to be from three to five 
miles an hour, they might travel an immense distance before the eggs 
or seeds were destroyed. JI am ashamed to say that I neglected the 
opportunity, whilst on the spot, of ascertaining whether this was actually 
the case. The attention of Naturalists has only lately been turned to 
the important subject of occasional means of wide dissemination of 
species of animals and plants. Unless such be shown to exist, it is 
impossible to solve some of the most difficult problems connected with 
the distribution of plants and animals. Some species, with most limited 
powers of locomotion, are found in opposite parts of the earth, without 
existing in the intermediate regions ; unless it can be shown that these 
may have migrated or been accidentally transported from one point to the 
other, we shall have to come to the strange conclusion that the same 
species had been created in two separate districts. 
Canoemen on the Upper Amazons live in constant dread of the 
“terras cahidas,” or landslips, which occasionally take place along the 
steep earthy banks, especially when the waters are rising. Large vessels 
are sometimes overwhelmed by these avalanches of earth and trees. I 
should have thought the accounts of them exaggerated, if I had not had 
an opportunity during this voyage of seeing one on a large scale. One 
morning I was awoke before sunrise by an unusual sound resembling 
the roar of artillery. I was lying alone on the top of the cabin ; it was 
very dark, and all my companions were asleep, so I lay listening. The 
sounds came from a considerable distance, and the crash which had 
aroused me was succeeded by others much less formidable. The first 
explanation which occurred to me was that it was an earthquake ; for, 
although the night was breathlessly calm, the broad river was much 
agitated and the vessel rolled heavily. Soon after, another loud explo- 
sion took place, apparently much nearer than the former one; then 
followed others. ‘The thundering peal rolled backwards and forwards, 
now seeming close at hand, now far off; the sudden crashes being often 
succeeded by a pause, or a long-continued dull rumbling. At the second 
explosion, Vicente, who lay snoring by the helm, awoke and told me it 
was a “terra cahida”; but I could scarcely believe him. The day 
dawned after the uproar had lasted about an hour, and we then saw the 
work of destruction going forward on the other side of the river, about 
three miles off. Large masses of forest, including. trees of colossal size, 
probably 200 feet in height, were rocking to and fro, and falling headlong 
one after the other into the water. After each avalanche the wave 
which it caused returned on the crumbly bank with tremendous force, 
and caused the fall of other masses by undermining them. ‘The line of 
coast over which the landslip extended was a mile or two in length ; the 
end of it, however, was hid from our view by an intervening island. It 
was a grand sight ; each downfall created a cloud of spray ; the concus- 
sion in one place causing other masses to give way a long distance from 
