CHAPTER XL 
ON THE PHYSICAL FEATURES OF THE VALLEY OF THE COLORADO. 
The topographic 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 reproduced, 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 find .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, re-entering angles, and often naked of soil and vege 
tation. 
Then we find lines of cliffs, 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 canons, 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 mauvaises terres, 
or bad-lands. These are dreary wastes naked hills, with rounded or con 
ical 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 arroyas. 
Where the mud rocks or sandy clays arid shales, of which the hills are 
composed, are interstratified with occasional harder beds, the slopes are 
terraced; and when these thinly bedded, though harder, rocks prevail, the 
