TOPOGRAPHY. 8 



westward direction ; the Gabilan Ridge has its origin in 

 36 10', and its course is north northwest ; the Contra Costa 

 Ridge appears in 37 10', and is parallel with the Gabilan. 

 These ridges and their intervening valleys make up the entire 

 slope between the summit of the Coast Range and the ocean, 

 from 34 20' to 38 30', beyond which line the regularity of 

 the formation ceases, and the valleys are small and crooked. 

 The Contra Costa Ridge forms the eastern boundary of the 

 Alameda plain, and separates Napa from Sonoma Valley. 

 The Gabilan Ridge, named after a prominent peak, the Gabi- 

 lan, in Monterey County, forms the backbone of San Mateo, 

 San Francisco, and Marin Counties, and separates the Santa 

 Clara from the Salinas Valleys. The valleys south of the Sa- 

 linas are the Cuvama, Santa Inez, and the Saticoy (or Santa 

 Clara of the South). The principal peaks of the Coast Range, 

 including San Bernardino, are in the Diablo Ridge. 



4. Coast JRivers. The rivers of the Coast Mountains 

 have necessarily but a short course. Those south of the bay 

 of San Francisco are the San Lorenzo, Pajaro, Salinas, Cu- 

 yama, Santa Inez, Saticoy (or Santa Clara), Los Angeles, San 

 Gabriel, Santa Ana, Saata Margarita, San Luis Rey, San 

 Dieguito, and San Diego. Some of these are large streams in 

 wet winters ; but, in the drought of autumn, all those south 

 of the Salinas are swallowed up in the sands before reaching 

 the ocean. Most of them are constant streams to within ten 

 or fifteen miles of their mouths. The Santa Ana, the largest 

 river on the southern coast, rises in Mount San Bernardino, 

 and is in its meanderings nearly one hundred miles long ; yet 

 only in very wet seasons, once in six or eight years, succeeds 

 in getting to the sea. The San Gabriel River sinks before 

 reaching Monte, in Los Angeles County, and, after passing 

 three miles under ground, rises again. The intervening space, 

 where there is no river, is very moist, sandy ground, through 

 which the water spreads and soaks. 



W. H. Emory, in his report as member of the Mexican 

 Boundary Commission, writes thus : 



