lii INTRODUCTION". 



denuded slope of the harder rocks ; on the east by the abnip 

 wall of the softer strata, most precipitous when capped b 

 harder material. The erosion, for the most part produced bj 

 water flowing from a distant source, has taken place on thfji 

 harder material at the bottom only of each trough, and thui 



the 



V* 



Leaying the weii-d, worthless regions north of the 36th 

 rallel, let us irlance for a moment at those forming Central 



Arizona, lying between the Colorado Chiquito and the Bio 



Gila. Nearly all this region has been greatly distui-bed by 



innumerable ranges of mountains 

 the surface is covered with the 



extinct, and with the drift washed from the mountain sides. 



Between the head- waters of the Eio Gila and the Colorado 

 Chiquito is a yery eleyatcd tract of country, chiefly occupied 

 by the various ranges kui 



wn as the Moeollon Moimtaius, 



■ds 



which shed theu' waters in a southern direction to form 

 Eio Gila, and in a north and north-western direction towa 

 the Colorado Chiquito. The hostile Indians, the Apaches, of 

 these regions have, up to the present time, so kept the wlute 



bay that no explorations have b 



h 



them ; and we know nothing of the country, except from the 

 few daring prospectors whom thirst for gold has led to nsK 

 tlieir lives in its pursuit. The reports of these men, who are 

 wonderfully shi-ewd and reliable, describe the land as being 

 very beautiful and of great fertility. Forests of noble pm^ 



enclosing well-watered 



onsiderable extent, clothed with lux^i' 



mountains 



reat 



* I have quoted Dr. Newberry at some length, because I feel that g^^^ 

 credit is due to h.lm for so clearly laying down those principles whicli, w ^^ 

 thoroughly grasped by the Western traveller, enable him to read the foce^ ^ 

 nature intelligently, and to account for much of what is very striking, ^_^ 

 manner satisfactory to himself, even though he may not be versed in geolPc • 



