70 PALEONTOLOGY 



lives in the great rivers of South America beyond the tidal 

 limit, and is found in British freshwater Oligocene strata. 



FlG 21. CORBULA GALLICA, LAMARCK, EOCENE, PARIS BASIN. 



(Natural Size.) 



Upper figure, complete shell from left side ; middle figure, interior of 

 left valve; lower figure, interior of right valve, p.s. , Pallial sinus; 

 x, resiliophore. (After Deshayes. ) 



10. Pholadomya is a genus which made its first ap- 

 pearance in the Lower Lias, was abundantly represented 



