of the Cuzco Valley, Peru. 



99 



the railroad paralleling the ITrubamba (here called the Vil- 

 canota) the lavas and associated intrusive rocks form a pali- 

 sade wall of large columns decorated by radiating sheaves and 

 fans composed of columns of small diameter (fig. 44). It is 



Fig. 44. 



Fig. 44. Wall of columnar lava lining the canyon of the Urubamba 

 between Cay-Cay and Rajchchi. Leon Campbell, photo. 



probable that the lava at this point formerly extended across 

 the Urubamba, thus effecting an important modification in the 

 drainage. 



