PART 11. CHAPTER XXIV. 



285 



Tertiary Plutonic Rocks in the Andes. 



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- 



