464 



CALIFORNIA ACADEMY OF SCIENCES 



[Proc. 4th Ser. 



Living: Fort Bragg, California (!), to Magdalena Bay 

 (and Cape San Lucas ?), Lower California. 



Material Examined: 



Valve 



Locality 



Collector 



Where Deposited 





Formation 



Period 



Ant.. 

 Int. . 

 Post. 

 Ant.. 

 Ant.. 



Int. . 

 Int. . 

 Post. 

 Post. 

 Ant.. 

 Int. . 

 Post. 

 Ant.. 



Int.. 



Post. 



Ant.. 



Int. . 



Post. 



Post. 



Chiton Bed, Pt. Fermin, Cal. 

 Chiton Bed, Pt. Fermin, Cal . 

 Chiton Bed, Pt. Fermin, Cal . 

 Chiton Bed, Pt. Fermin, Cal. 

 Chiton Bed, Pt. Fermin, Cal. 



Chiton 

 Chiton 

 Chiton 

 Chiton 

 Chiton 

 Chiton 

 Chiton 

 Chiton 



Bed, Pt. 

 Bed, Pt. 

 Bed, Pt. 

 Bed, Pt. 

 Bed, Pt. 

 Bed, Pt. 

 Bed, Pt. 

 Bed, Pt. 



Fermin, Cal . 

 Fermin, Cal . 

 Fermin, Cal . 

 Fermin, Cal , 

 Fermin, Cal . 

 Fermin, Cal . 

 Fermin, Cal . 

 Fermin, Cal . 



Chiton Bed, Pt. Fermin, Cal. 

 Chiton Bed, Pt. Fermin, Cal . 



Near lighthouse, Pt. Fermin, 

 Cal 



Near lighthouse, Pt. Fermin, 

 Cal 



Near lighthouse, Pt. Fermin, 

 Cal 



Deadman Id., San Pedro, Cal. 



E. P. Chace, 1918 



E. P. Chace, 1918 



E. P. Chace, 1918 



E.P.&E.M. Chace, 1918 

 E. P. & E. M. Chace, 1918 



E. P. & E. M. Chace, 1918 

 E.P.&E.M. Chace, 1918 

 E. P. & E. M. Chace, 1918 

 E.P.&E.M. Chace, 1918 



E. P. Chace, 1920 



E. P. Chace, 1920 



E. P. Chace, 1920 



E. P. Chace & S. S. Berry, 



1920 



E. P. Chace & S. S. Berry, 



1920 



E. P. Chace & S. S. Berry, 



1920 



E.P.&E.M. Chace, 1918 



E. P. & E. M. Chace, 1918 



E. P. & E. M. Chace, 1918 

 Arnold Coll 



Berry Coll. Cat. 4042 

 Berry Coll. Cat. 4042 

 Berry Coll. Cat. 4042 



Chace Coll 



Berry Coll. Cat. 4105 



Chace Coll 



Berry Coll. Cat. 4076 

 Berry Coll. Cat. 4105 

 Berry Coll. Cat. 4105 



Chace Coll 



Chace Coll 



Chace Coll 



Chace Coll 



Berry Coll. Cat. 4965 



Cal. Acd. Sci 



Chace Coll 



Berry Coll. Cat. 4111 



Berry Coll. Cat. 4111 



Berry Coll. Cat. 4111 

 Bept. Geology, 

 Stanford Univ .... 



[ 946 

 [ 947 

 [ 948 

 [1031 

 [1085 



}[1032 

 [1086 

 [1087 

 [1033 

 [1365 

 [1365 

 [1365 



f 

 [1412 



111413: 



U1414 

 [1102 

 [1103 

 [1104 

 [ 684 



Lower San Pedro. 

 Lower San Pedro . 

 Lower San Pedro. 

 Lower San Pedro. 

 Lower San Pedro. 



Lower 

 Lower 

 Lower 

 Lower 

 Lower 

 Lower 

 Lower 



San Pedro. 

 San Pedro. 

 San Pedro. 

 San Pedro 

 San Pedro . 

 San Pedro. 

 San Pedro. 



Lower San Pedro 

 Lower San Pedro. 

 Lower San Pedro. 

 Lower San Pedro. 

 Lower San Pedro. 

 Lower San Pedro. 



Pleistocene 

 Pleistocene 

 Pleistocene 

 Pleistocene 

 Pleistocene 



Pleistocene 

 Pleistocene 

 Pleistocene 

 Pleistocene 

 Pleistocene 

 Pleistocene 

 Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Remarks: Although in the living state this is one of the 

 most abundant California chitons, I have been able to identify 

 as this species scarcely any fossil material except that from the 

 Lower San Pedro beds at Point Fermin. Both fossil and 

 recent specimens are usually easy to differentiate from small 

 specimens of the related forms, acrior and conspicuus, by the 

 narrower, more elongate outline ; the convex, straight, or (when 

 perfect) very weakly concave head valve; the finely plicate 

 sculpturing (often eroded) of the central areas, which becomes 

 prettily netted toward the sides; and the numerous, fine, rela- 

 tively straight, radiating riblets of the lateral and terminal 

 areas. There are also girdle characters of value which are of 

 course unavailable to the paleontologist. 



