90 



THE DESERT 



Color of 



mountain 



walls. 



Weather 

 staining. 



Influence of 

 the air. 



Grand Canyon of the Yellowstone. The reds are 

 always salmon-colored, terra-cotta, or Indian 

 red ; the greens are olive-hued, plum-colored, 

 sage-green ; the yellows are as pallid as the 

 leaves of yellow roses. Fresh breaks in the 

 wall of rock may show brighter colors that 

 have not yet been weather-worn, or they may 

 reveal the oxidation of various minerals. Often 

 long strata and beds, and even whole mountain 

 tops show blue and green with copper, or 

 orange with iron, or purple with slates, or white 

 with quartz. But the tones soon become sub- 

 dued. A mountain wall may be dark red with- 

 in, but it is weather-stained and lichen-covered 

 without; long-reaching shafts of granite that 

 loom upward from a peak may be yellow at 

 heart but they are silver-gray on the surface. 

 The colors have undergone years of " toning 

 down " until they blend and run together like 

 the faded tints of an Eastern rug. 



But granted the quantity and the quality of 

 local colors in the desert, and the fact still re- 

 mains that the air is the medium that influ- 

 ences if it does not radically change them all. 

 The local hue of a sierra may be gray, dark red, 

 iron-hued, or lead-colored ; but at a distance, 

 seen through dust-laden air, it may appear 



