Geol.— Vol. I.] DAVIDSON— SUBMERGED VALLEYS. 8l 



Cape Mendocino; and if attention be given to the oro- 

 graphical features of the coast, it will be seen that the Coast 

 Ranges from the southward and southeastward seem to end 

 abruptly upon the ocean front in latitude 40° 27'. 



In October, 1886, the writer presented to the California 

 Academy of Sciences some of the physical features of the 

 submerged valleys under the high mountains immediately 

 behind Capes Mendocino and Gorda, the more especially 

 because the valleys lie nearly at right angles to the over- 

 hanging range. Subsequently he gathered all the data 

 available for all the valleys, drew the contour lines to exhibit 

 their peculiarities, and added memoranda of the character of 

 the bottom and of the adjacent plateau. To the California 

 series were added others partly developed by the U. S. 

 Hydrographic Survey along the coast of Lower California. 

 When the first short announcements of these valleys were 

 made, they were known as " submarine valleys;" later 

 they were designated " submerged." 



The following is a condensed description of those sub- 

 merged valleys, the characters of which appear in the con- 

 tours thus drawn: — 



I. The Soledad or La Jolla Valley. 



This valley heads southeastwardly into the slight recession 

 of the shore-line on the north side of Point La Jolla. This 

 point is the northern extremity of an almost isolated sand- 

 stone hill named Soledad, lying between the northern part 

 of False Bay and La Jolla. The extent of the hill is about 

 3^ miles NW. and SE., and very nearly as wide E. NE. 

 and W. NW. The ocean front is a three mile stretch of 

 rocky, jagged shore, rising rather sharply to over 800 feet 

 in one and one half miles. The higher part of the hill is 

 to the W. NW. There is no very marked depression be- 

 tween this hill and the high land to the N. NE. ; certainly 

 nothing to indicate a submerged valley. The head of the 

 valley is within one third of a mile of the deepest part of 



