230 



University of California. 



[Vol. 2. 



coast below the present sea level would appear to be indicated by 

 the deposits on Santa Rosa in which these remains are found. It 

 should be noted that the only fossil, other than vertebrate 

 remains, which has been described as occurring in these deposits is 

 a fresh-water mollusk (Physa).* It is evident, from the meager 

 descriptions which we have of these deposits, that they should be 

 more thoroughly examined before any definite conclusions con- 

 cerning the latter coastal movements can be drawn from them. 



It is probable that, while the oscillations of post-Pliocene times 

 have been sufficient to connect the northern islands with the 

 mainland, none of the southern islands have had such connection 

 since the post-Miocene period of erosion. 



The most recent movement of the coast, as indicated by 

 drowned valleys and submarine features, is a comparatively slight 

 depression, the evidence for which, on the southern California 

 coast, has already been given in detail. The later history of the 

 coast seems, therefore, to be most satisfactorily summed up in a 

 single post-Pliocene elevation, interrupted by minor reverse move- 

 ments, of which this most recent depression is probably one. 



Whether or not future investigation shall lead to modification 

 of the details of the coastal movements as here outlined, is imma- 

 terial to the main conclusions of the present paper, the principal 

 point which it aims to establish being the fact that the latest general 

 movements of the islands and coast line of southern California 

 have been the same. 



University of California, 



June, 1900. 



*Am. Geo]., Vol. V, 1S90, p. 51. 



