lOO CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



elevation of 10,000 feet and there are a few passes across the 

 peninsula. Along the Pacific front the coast is much 

 broken, rocky, and mountainous, reaching elevations of 

 over 3,000 feet in less than five miles. A series of islands 

 and rocks about 150 miles off shore and parallel with the 

 peninsula would appear to indicate a submarine range of 

 mountains, with profound depths between them, and hence 

 to the coast. 



2. The One Hundred-Fathom Plateau. 



Along the whole line of the Pacific Coast of Lower Cal- 

 ifornia, 700 miles, the lOO-fathom plateau is found in but few 

 places. For example, from Cape Lazaro in latitude 24° 

 45' to Abreojos Point in latitude 26° 45' (130 miles NW.), 

 under the broad indentation of this shore, the plateau of 

 100 fathoms stretches out 35 to 40 miles without the sign of 

 a submerged valley through it. At the southeastern part of 

 this plateau the prolongation of the mountainous island of 

 Santa Margarita and Point Lazaro is clearly indicated for 

 75 miles to the northwest. At the northwestern part the 

 depth drops to 2,000 fathoms only 30 miles from the plateau. 



There is another lOO-fathom plateau inside of Cerros 

 Island, latitude 28° 15', covering the whole of the Sebastian 

 Vizcaino Bay, 60 miles wide to the lOO-fathom line. 

 Twenty miles outside of San Benito Island (close to Cerros) 

 the depth is 1,300 fathoms. This great bay reaches in well 

 to the southeast and is bordered by low sand dunes and 

 great lagoons, behind which the mountains retreat far in- 

 land; yet there is no indication of any submerged valley 

 across the loo-fathom plateau. 



From the northern part of this bay to Cape San Quentin, 

 in latitude 30° 20', the loo-fathom plateau approaches the 

 steep coast-line within six or seven miles. 



3. The San Pablo Submerged Valley. 



Point San Pablo lies in latitude 27° 13' and is one of the 

 prominent headlands along the west coast, projecting beyond 



