SAXTA OATALINA MOUNTAINS. 



251 



Figure 50. Burros laden with camping outfit. Castle Rock may be 

 seen above and between the human figures. 



PIMA CANOX AND CASTLE ROCK IX THE SAXTA 

 CATALINA MOUXTAIXS. 



By Professou Frajncis E. Lloyu. 



In company with Dv. \\'. A. Cannon and Dr. B. E. Liv- 

 ingston, I recently made a trip to Pima canon in the Santa 

 Catalina Monntains, distant some eighteen miles from the 

 city of Tucson, Arizona. The stretch of country between Tucson 

 and the mountains, though really considerable in extent, looks 

 to the eye like the proverbial morning's walk. It is indeed 

 only after making the distance on foot that one appreciates the 

 real extent of the country. It is a hard walk of six hours, part 

 of the way through the level mesa and part through the rough 

 and stony foothills which rise by a gentle gradient to the more 

 sudden slope of the moiintains themselves. 



The mesa is clothed with a growth of Mexican greasewood 

 with here and there a clump of cholla, and occasionally plants 

 of a species of tree opuntia (0. npinosior) with yellow or ma- 



