PLATE XXIV. 



Fig-. 



154. 





154, a. 



Pig. 



155. 



Fig. 



156. 



Fig. 



157. 



Fig. 



158. 



Fig. 



159. 



Fig. 



100. 



Fig. 



161. 



Fig. 



162. 





162, a. 



Fig. 



163. 



Fig. 



164. 



Fig. 



166. 



Fig. 



169. 



Fig 



170. 





170, a, 



Fig 



171. 



Fig 



254. 



Cardium Cqopehii. Natural size. 

 Side view, outline. 



C. Brewerii. Natural size. 



C. (Pkotocardium) Placerensis. Magnified. 



Cardita Hornii. Natural size. 



Lucina nastjta. Magnified. 



L. i'Ostradiata. Magnified. 



L. subcircularis. Natural size. 



Astarte Conradiana. Natural size. 



Eriphyla umbonata. Natural size. 

 Hinge of both valves, magnified. 



Crassatella grandis. Young. Natural size. 



Unio penultimus. Natural size. 



Modiola ornata. Natural size. 



Crenella concentrica. Magnified. 



? Loripes dubia. Natural size. 

 b. Hinge. 



«. 



L. dubia. Natural size. From Chico Creek. 



Lucina cumulata. Magnified. 



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172 



173 



173 

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 175 

 175 

 176 

 178 

 180 



181 

 182 

 184 

 186 

 177 



177 

 176 



