INTERMONT PLATEAUS OF THE PACIFIC 111 



grass, interspersed with colonies of low cacti. The canons 

 vary greatly as regards vegetation ; some of them have 

 naked walls with nothing but crooked pines sticking 



l. Fig. 32. A typical timbered canon in the 

 Colorado Region. 



occasionally out of crevices ; others are clothed with 

 luxuriant and regular pine-forests, including the yellow 

 pine and the douglas or red fir. 



A few valleys, like those of the Rio Grande and San- 



