270 



THE EARTH'S CRUST 



Dissected Plateaus. If a plateau has been elevated 

 for considerable time in a region of abundant rainfall, the 

 streams extend their courses in networks, thoroughly dis- 

 secting the area and leaving between their courses only 

 narrow remnants of the upland. The valleys are still 

 deep, but the intervening uplands are of small extent. 

 Traveling over the region in any direction except along 



THE ENCHANTED MESA, NKW MEXICO 

 With old Indian village in foreground. 



the stream courses is a continual process of climbing out 

 of and into valleys. 



There is very little level space that can be used for cul- 

 tivation, and on account of the steepness of the slop*- if 

 is very hard to build roads. The river valleys an; so narrow 

 that unless the roads are perched high up on the sides, 

 they are liable to be swept away at the time of flood. Fann- 

 ing in these regions is very discouraging because of the dim'- 



