312 _ CALIFORNIA ACADEMY OF SCIENCES. 



Blake reports* the following from this horizon: 



Telliua cougesta Conrad. 

 Meretrix traskii Conrad sp. 

 Merceuaria perlaminosa Conrad. 



In addition Professor Lawson notest the following 



forms : 



Area sp. (Nov. ?) 



Saxidomus sp. 



Leda sp. (Nov. ?) 



Luciua like L. creuulata. 



Clementia? sp. 



Young Cardium, or small Venericardia. 



Macoma sp. (Nov.?) 



Among those mentioned by Gabb in vol. i of the Pal- 

 eontology of Cal. is Turritella hofmanni Gabb. 



Though none of these species except Lucina borealis 

 Linn, occur on the east coast, by a comparison of similar 

 forms Conrad concluded that this formation was Miocene. 

 And as we have both above and below species almost 

 identical with Miocene species of the east coast, we may 

 accept his determination. 



THE MERCED SERIES. 



The beds which will be assigned to this division have 

 alternately been called Miocene and Pliocene, but of re- 

 cent years have come to be considered Pliocene. The 

 field-work of the writer seems to show that they are Pli- 

 ocene, though at the bottom probably transitional from 

 the Miocene. This formation is of considerable thick- 

 ness and is very fossiliferous. Its location is very favor- 

 able for the exposure of fine sections, so that along the 

 seaboard it is exposed almost continuously the whole 

 length of the Santa Cruz Mountains, and in cliffs aver- 

 aging perhaps 75 feet high (see plate xxiv), but on Seven 



* Geol. Eecon. of Cal., 1858, pp. 182, 179. 



t Univ. of Cal., Bull. Dept. Geol., vol. i, p. 27. 



