Geol.— Vol. I.] DAVIDSON— SUBMERGED VALLEYS. 75 



at Points Dume and Mugu, but continued seaward through 

 Anacapa, Santa Cruz, Santa Rosa, and San Miguel Islands. 



North of Point Arguello are two or three valleys which 

 lie between high ranges parallel to the Santa Ynez and 

 which open directly upon the ocean. 



Approaching San Luis Obispo Bay, where the Monte del 

 Buchon is 1,830 feet high, the main range of the Coast 

 mountains comes from the southeastward, reaches 4,000 

 feet elevation behind San Simeon Bay, and comes boldly 

 upon the ocean a little north of Piedras Blancas, whence it 

 runs to Carmel Bay for about 50 miles and forms the most 

 compact and precipitous ocean barrier on the Pacific Coast. 

 It reaches a culmination of 5,020 feet less than three miles 

 from the sea, in latitude 36° 03'. Off this range the 2,000 

 fathom depth of the Pacific is only 52 miles from the shore. 



At Monterey Bay there is a complete breaking down of 

 the Coast Range for 25 miles, with the mountains receding 

 well inland. Into this broad and deep bight heads the finest 

 of the submerged valleys. 



2. Santa Cruz to Cape Mendocino. 



Northward of Monterey Bay, from Santa Cruz, in lati- 

 tude 36° 57', to the Golden Gate, in latitude 37° 48', the 

 great mountain ridge of the peninsula of San Francisco 

 reaches 3,790 feet elevation, and offers an unbroken 

 barrier along the ocean front for 50 miles, to the Golden 

 Gate. This ridge is continued seaward, as shown by the 

 submarine indications through the Farallones groups and the 

 Cordell Bank. 



The remarkable cleft in the Coast Ranges at the Golden 

 Gate has no representative feature through the plateau of 

 the Gulf of the Farallones. Just outside of this 100 fathom 

 plateau commences the descent of the bottom to 2,000 

 fathoms, which depth is reached in 50 miles from the South- 

 east Farallon. 



Part of the ocean barrier is continued outside of the spur 

 of Mount Tamalpais (2,590 feet elevation), in a parallel 



