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PASSAGE OF CORDILLERA. March, 1835. 



created in two different countries, we ought not to expect any- 

 closer similarity between the organic beings on opposite sides 

 of the Andes, than on shores separated by a broad strait of 

 the sea. In both cases we must leave out of the question 

 those kinds which have been able to cross the barrier, whe- 

 ther of salt water or solid rock.* 



A great number of the plants and animals were absolutely 

 the same, or most closely allied with those of Patagonia, 

 We here have the agouti, bizcacha, three species of armadillo, 

 the ostrich, certain kinds of partridges, and other birds, none 

 of which are ever seen in Chile, but are the characteristic 

 animals of the desert plains of Patagonia. We have likewise 

 many of the same (to the eyes of a person who is not a bo- 

 tanist) thorny stunted bushes, withered grass, and dwarf 

 plants. Even the black slowly-crawling beetles are closely 

 similar, and some, I believe, on rigorous examination, abso- 

 lutely identical. It had always been a subject of regret to 

 me, that we were unavoidably compelled to give up the 

 ascent of the St. Cruz river before reaching the mountains. 

 I always had a latent hope of meeting with some great 

 change in the features of the country ; but I now feel sure, 

 that it would only have been following the plains of Patagonia 

 up an ascent. 



March 24th. — Early in the morning I climbed up a 

 mountain on one side of the valley, and enjoyed a far-extended 

 view over the Pampas. This was a spectacle to which I had 

 always looked forward with interest, but I was disappointed. 

 At the first glance there was a strong resemblance to a dis- 

 tant view of the ocean, but in the northern parts many irre- 

 gularities in the surface were soon distinguishable. The 

 most striking feature in the scene consisted of the rivers, 



* This is merely an illustration of the admirable laws first laid down 

 by Mr. Lyell of the geographical distribution of animals as influenced by 

 geological changes. The whole reasoning, of course, is founded on 

 the assumption of the immutability of species. Otherwise the changes 

 might be considered as superinduced by different circumstances in the 

 two regions during a length of time. 



