Iv.
p. 199.
[6] A similar interesting case is recorded in the Madras
Medical Quart. Journ., 1839, p. 340. Dr. Ferguson, in his
admirable Paper (see 9th vol. of Edinburgh Royal Trans.),
shows clearly that the poison is generated in the drying
process; and hence that dry hot countries are often the most
unhealthy.
CHAPTER XVII
GALAPAGOS ARCHIPELAGO
The whole Group Volcanic - Numbers of Craters - Leafless
Bushes Colony at Charles Island - James Island - Salt-lake in
Crater - Natural History of the Group - Ornithology, curious
Finches - Reptiles - Great Tortoises, habits of - Marine
Lizard, feeds on Sea-weed - Terrestrial Lizard, burrowing
habits, herbivorous - Importance of Reptiles in the
Archipelago - Fish, Shells, Insects - Botany - American Type
of Organization - Differences in the Species or Races on
different Islands - Tameness of the Birds - Fear of Man, an
acquired Instinct.
SEPTEMBER 15th. - This archipelago consists of ten
principal islands, of which five exceed the others in
size. They are situated under the Equator, and between
five and six hundred miles westward of the coast of
America. They are all formed of volcanic rocks; a few
fragments of granite curiously glazed and altered by the
heat, can hardly be considered as an exception. Some of
the craters, surmounting the larger islands, are of immense
size, and they rise to a height of between three and four
thousand feet. Their flanks are studded by innumerable
smaller orifices. I scarcely hesitate to affirm, that there
must be in the whole archipelago at least two thousand
craters. These consist either of lava or scoriae, or of finely-
stratified, sandstone-like tuff. Most of the latter are
beautifully symmetrical; they owe their origin to eruptions of
volcanic mud without any lava: it is a remarkable circumstance
that every one of the twenty-eight tuff-craters which
were examined, had their southern sides either much lower
than the other sides, or quite broken down and removed. As
all these craters apparently have been formed when standing
in the sea, and as the waves from the trade wind and the
swell from the open Pacific here unite their forces on the
southern coasts of all the islands, this singular uniformity
in the broken state of the craters, composed of the soft and
yielding tuff, is easily explained.
Considering that these islands are placed directly under
the equator, the climate is far from being excessively hot;
this seems chiefly caused by the singularly low temperature
of the surrounding water, brought here by the great southern
[map]
Polar current. Excepting during one short season, very
little rain falls, and even then it is irregular; but the clouds
generally hang low. Hence, whilst the lower parts of the
islands are very sterile, the upper parts, at a height of a
thousand feet and upwards, possess a damp climate and a
tolerably luxuriant vegetation. This is especially the case
on the windward sides of the islands, which first receive and
condense the moisture from the atmosphere.
![The Voyage Of The Beagle By Charles Darwin
- Vii. p. 324.
[5] Political Essay on the Kingdom of New Spain, vol. iv.
p. 199.
[6] A similar interesting - Page 298](../images/travel.jpg)
