lyo NOTES OF A NATURALIST. 



the channels of Patagonia had been most imperfectly 

 explored, Darwin was led to infer a much closer 

 resemblance between the orographic features of the 

 two regions than it is now possible to admit. He 

 supposed the greater part, if not the whole of the 

 Chilian coast, to be bordered by mountain ranges 

 running parallel to the main chain of the Cordillera, 

 thus forming a succession of nearly level basins lying 

 between these outer mountains and the main range, 

 each being drained through a tranverse valley which 

 cuts through the outer range. Such a conformation 

 of the surface would undoubtedly resemble what we 

 find on the western coast of South America, between 

 the Gulf of Ancud and the Straits of Magellan. But 

 the facts correspond with this view only to a limited 

 extent. 



The tints laid down on Petermann's map to indicate 

 successive zones of height above the sea are far from 

 being completely accurate, but slight errors of detail 

 do not affect the general conclusions to which w^e 

 must arrive. If we carry the eye along from north to 

 south, we find a succession of great buttresses or 

 promontories of high land projecting westward from 

 the main range, between which relatively deep valleys 

 carry the drainage towards the Pacific coast. The 

 effect of a continuous sinking of the land would be to 

 produce a series of deep bays running far inland to 

 the base of the Cordillera, and further depression 

 might show here and there some scattered islets, but 

 nothing to resemble the almost continuous range of 

 mountainous islands that separate the channels of 

 Patagonia from the ocean. As far as it is possible to 



