8 



H. E. Gregory — A Geologic Beconnaissance 



Western Plateau and an Eastern Plateau by the sunken interior 

 basin holding the waters of Lake Titicaca. In the latitude 

 of Cuzco these relations are not duplicated ; the Andean plateau 

 is practically uninterrupted and the terms Eastern Cordillera 



Fig. 2. Outline map of a portion of Southern Peru, showing the location 

 of Cuzco Valley. 



and Western Cordillera have little significance. The dominant 

 topographic feature of southern Peru is a widely extended 

 plateau, not chains of lofty mountains, as represented in 

 standard atlases. 



Belief. — The rim of the Cuzco Valley stands at an average 

 elevation of about 13,500 feet and is surmounted by peaks 



