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 Rep- 

 tilesGreat Tortoises, habits of Marine Lizard, feeds on Sea- 

 weed Terrestrial Lizard, burrowing habits, herbivorous Impor- 

 tance 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. 



C^EPTEMBER ijth. This archipelago consists of ten 

 i\ principal islands, of which five exceed the others in 

 size. They are situated under the Equator, and be- 

 tween 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 beau- 

 tifully symmetrical; they owe their origin to eruptions of 

 volcanic mud without any lava: it is a remarkable circum- 

 stance 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 



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