376 CHARLES DARWIN 



sions, and leading to a pass across the Cordillera, yet it is 

 completely dry, excepting perhaps for a few days during 

 some very rainy winter. The sides of the crumbling moun- 

 tains were furrowed by scarcely any ravines ; and the bottom 

 of the main valley, filled with shingle, was smooth and nearly 

 level. No considerable torrent could ever have flowed down 

 this bed of shingle; for if it had, a great cliff-bounded chan- 

 nel, as in all the southern valleys, would assuredly have been 

 formed. I feel little doubt that this valley, as well as those 

 mentioned by travellers in Peru, were left in the state we now 

 see them by the waves of the sea, as the land slowly rose. I 

 observed in one place, where the Despoblado was joined by a 

 ravine (which in almost any other chain would have been 

 called a grand valley), that its bed, though composed merely 

 of sand and gravel, was higher than that of its tributary. 

 A mere rivulet of water, in the course of an hour, would have 

 cut a channel for itself; but it was evident that ages had 

 passed away, and no such rivulet had drained this great tribu- 

 tary. It was curious to behold the machinery, if such a term 

 may be used, for the drainage, all, with the last trifling excep- 

 tion, perfect, yet without any signs of action. Every one 

 must have remarked how mud-banks, left by the retiring tide, 

 imitate in miniature a country with hill and dale; and here 

 we have the original model in rock, formed as the continent 

 rose during the secular retirement of the ocean, instead of 

 during the ebbing and flowing of the tides. If a shower of 

 rain falls on the mud-bank, when left dry, it deepens the 

 already-formed shallow lines of excavation ; and so it is with 

 the rain of successive centuries on the bank of rock and soil, 

 which we call a continent. 



We rode on after it was dark, till we reached a side ravine 

 with a small well, called " Agua amarga." The water 

 deserved its name, for besides being saline it was most offen- 

 sively putrid and bitter ; so that we could not force ourselves 

 to drink either tea or mate. I suppose the distance from the 

 river of Copiapo to this spot was at least twenty-five or thirty 

 English miles; in the whole space there was not a single 

 drop of water, the country deserving the name of desert in 

 the strictest sense. Yet about half way we passed some old 

 Indian ruins near Punta Gorda: I noticed also in front of 



