CHAPTER VI. 
THE VALLEY OF THE RIO GILA, AND COUNTRY LYING BETW. 
THE RIO COLORADO OF THE WEST AND THE PACIFIC OCEAN. 
CONTRIBUTED BY CAPTAIN WILLIAM F. CoLTon. 
The Rio Gila and its Tributaries. The Plateaux beyond the Valley. —Cul 
Valley.—Insufficiency of Rain-fall.—Great Heat of 
io Colo: 
Diego Bay.—The Towa. —Clinnate of San Di ~ ths finest in America. 
Southern California 
Tue Gila River, rising in the Mogollon ranges of 
Mexico, has a general westerly course, passing into 
traversing the entire breadth of Arizona, and emp 
into the Rio Colorado just opposite the boundary betw 
California and Lower California. From the north it 
numerous affluents breaking through a region frequentl 
mountainous and always much broken, but with beaw 
and fertile valleys well supplied with timber and animal life 
and remarkable for the evidences of an ancient civilisation 
found in the ruins of well-built towns and extensive acequias 
constructed of cut stone. 
From the south it receives but few branches, the Rio § 
Pedro being the most important. Below the mouth of t 
San Pedro, the valley of the Gila for a distance of twel 
miles is open, and varies from one to two miles in widt 
The river then “cafions,” and for about thirty miles wi 
its devious way between frowning cliffs and precipices. 
the lower end of these cafions to its mouth the valley is op 
