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Darwin, Charles, 1809-1882

"The Voyage of the Beagle"


Terrestrial Lizard, burrowing habits, herbivorous.
Importance of reptiles in the Archipelago.
Fish, shells, insects.
Botany.
American type of organisation.
Differences in the species or races on different islands.
Tameness of the birds.
Fear of man an acquired instinct.
SEPTEMBER 15, 1835.
(PLATE 80. GALAPAGOS ARCHIPELAGO.)

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 and 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.


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