THE 



POPULAR SCIENCE 

 MONTHLY. 



AUGUST, 1875. 



PHYSICAL FEATURES OF THE COLOEADO YALLEY.' 



Br Major J. W. POWELL. 



I. Mountains and Valleys. 



THE topographical features of the valley of the Colorado, or the 

 area drained by the Colorado River and its tributaries, are, in 

 many respects, unique, as some of these features, perhaps, are not re- 

 produced, except to a very limited extent, on any other portion of the 

 surface of the globe. Mountains, hills, plateaus, plains, and valleys, 

 are here found, as elsewhere throughout the earth ; but, in addition 

 to these topographic elements in the scenic features of the region, we 

 tind buttes, outlying masses of stratified rocks, often of great altitude, 

 not as dome-shaped or conical mounds, but usually having angular 

 outlines ; their sides are vertical walls, terraced or buttressed, and 

 broken by deep, reentering angles, and often naked of soil and vege- 

 tation. 



Then we find lines of clifis, abrupt escarpments of rock, of great 

 length and great height, revealing the cut edges of strata swept away 

 from the lower side. Thirdly, we find caiions, narrow gorges, scores 

 or hundreds of miles in length, and hundreds or thousands of feet in 

 depth, with walls of precipitous rocks. 



In the arid region of the Western portion of the United States, 

 there are certain tracts of country which have received the name of 

 3fauvaises Terres, or Bad Lands. These are dreary wastes naked 

 hills, with rounded or conical forms, composed of sand, sandy clays, 

 or fine fragments of shaly rocks, with steep slopes, and, yielding to 

 the pressure of the foot, they are climbed only by the greatest toil, 

 and it is a labor of no inconsiderable magnitude to penetrate or cross 

 such a district of country. The steep hills are crowded together, and 

 the water-ways separating them are deep array as. Where the niud- 



* From " Report on United States Geological and Geographical Survey of the Terri- 

 tories. Second Division." Major J. W. Powell in charge. 

 VOL. VII. 25 



