PLATE XXIV. 



PAGE 



Fig. 154. Cardium Cooperii. Natural size. 172 



154, a. Side view, outline. 



Fig. 155. C. Brewerii. Natural size. 173 



Fig. 156. C. (Protocardium) Placerensis. Magnified. 173 



Fig. 157. Cardita Hornii. Natural size. 174 



Fig. 158. Lxjcina nasxjta. Magnified. 175 



Fig. 159. L. postradiata. Magnified. 175 % 



Fig. 160. L. suBciRCULARis. Natural size. 176 



Fig. 161. Astarte Conradiana. Natural size. 178 



Fig. 162. Eriphyla umbonata. Natural size. 180 



162, a. Hinge of both valves, magnified. 



Fig. 163. Crassatella grandis. Young. Natural size. 181 



Fig. 164. Unio penultimus. Natural size. 182 



Fig. 166. Modiola ornata. Natural size. 184 



Fig. 169. Crenella conoentrica. Magnified. 186 



Fig. 170. ? Loripes dubia. Natural size. 177 

 170, a, b. Hinge. 



Fig. 171. L. dubia. Natural size. From Chico Creek. 177 



Fig. 254. Lucina cumulata. Magnified. 176 



