jfan. 1 6, 1879] 



NATURE 



had many more than now ; and every branch and every 

 twig of a stream here runs in a canon. The land is 

 honey-combed with them. To cross it, except in certain 



249 



specified ways, is a feat reserved exclusively to creatures 

 endowed with wings. The region is a desert of the 

 most formidable description. A few attenuated streams 



Fig. 2. — Grand Can;.n of the C.Lradj (6,200 feet deep). 



meander through it, but usually in cafions of which the 

 bottoms are somewhere between the earth's surface and 

 centre. The springs will not average one to a thousand 

 square tailes. But in the High Plateaus, at levels above 



7,500 feet, we find a moist climate, exuberant vegetation, 

 and hundreds of sparkling streams. 



During Cretaceous times, the Plateau Country was a 

 marine area. After 4,000" feet of Cretaceous strata were 



