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



Valley, and have been well described by Gabb, White, and 

 others; while for the older division of the same epoch the 

 localities are mostly new or have not yet become perfectly 

 known. It seems to be especially important that the Lower 

 Chico should be studied in such a manner. 



Of the Lower Chico localities selected for study, two lie 

 to the north and two to the south of the Great Valley basin, 

 and are as follows: {a) near Phoenix, Jackson County, Or- 

 egon; (<5) Henlev, Siskiyou County, California; (c) Silver- 

 ado Canyon (Bowers, 1890), Orange County, California; 

 (<^/) near San Diego, San Diego County, California, including 

 localities at Point Loma and La Jolla. 



Locality (c), Silverado Canyon, is intended to represent 

 the Lower Chico beds of the Santa Ana Mountains, 

 Orange County. The fauna of this horizon has recently 

 been reinforced by collections sent to the State University 

 by Dr. Stephen Bowers of Los Angeles. Some of the 

 localities from which his collections were made are very 

 near the Silverado Canyon, and hence are included with it. 

 Bowers' Canyon is thirty miles northwest of Los Angeles, 

 and from the fossils furnished by this locality it belongs to 

 the same horizon. 



Species occur in the following lists that are referred 

 to locality (c) by use of the letter '* R," as explained 

 in the foot-note. 



