180 RESOURCES OF CALIFORNIA. 



Bay ; the San Antonio slough, opposite San Francisco city ; 

 the Petaluma, Sonoma, and Napa sloughs, opening into San 

 Pablo Bay ; and Suisun and Pacheco sloughs, opening into 

 Suisun Bay. 



The navigation of the Colorado is beset by many difficulties. 

 The tide rises 28 feet at the mouth of the river, and some- 

 times advances with an immense bore or wave, which is dan- 

 gerous to small vessels. In the lower part of the river the 

 sand-bars are numerous, and they frequently shift their posi- 

 tions. The transportation is done by small tug steamers, draw- 

 ing about two feet of water, the freight being placed on 

 barges. The boats tie up to the bank in the evening, to avoid 

 the risk of running in the dark. The distances from the 

 mouth of the river, or Victoria Bay, are 150 miles to Fort 

 Yuma, 453 miles to Hardyville, and 543 miles to Callville. 

 The last point is the head of possible navigation, and there 

 the ordinary surface of the stream is 780 feet above the sea, 

 showing an average descent of about a foot and five inches to 

 the mile. Hardyville is the actual head of navigation, and 

 steamers usually take ten days for the trip from the mouth of 

 the river. 



The State has at present one navigable canal, built mainly 

 for the purpose of irrigation, but little use is made of it. Sev- 

 eral large canals will undoubtedly be constructed within a 

 few years. 



132. Passes. The passes on the mountains which fence in 

 the valleys of California are important elements in determin- 

 ing the course which commerce must take. Among the passes 

 in the Coast Range, are the following : 



PASSES. ELEVATION. LATITUDE. 



<deg. min. 



Livermore Pass 686 37 42 



Pacheco Pass .... 37 oo 



Panoche Pass 



Cajon de Tenoco Pass 34 40 



San Francisquito Pass 3>437 34 35 



