PART II. CHAPTER XXIV. 



285 



Tertiary Plutonic Rocks in the Andes. 



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II 





tertiary plutonic rocks laid open to view. What we already 

 know of the structure of the Chilian Andes seems to realize this 

 expectation. In a transverse section, examined by Mr. Darwin, 

 between Valparaiso and Mendoza, the Cordillera was found to 

 consist of two separate and parallel chains, formed of sedimen- 



