^70 



PROCEEDINGS OF THE ACADEMY OF 

 12 3 4 5 6 



F. coronatum Con. 

 Miocene (St. Mary's). 

 St. Mary's River, Md. 



F. rugosum Con. 

 Miocene (St. Mary's). 

 St. Mary's River, Md. 



F. canaliculatum (L.). 

 Pleistocene. 

 Cornfield Harbor, Md. 



F. pyrmn (Dill.). 



Recent. 



Gulf Coast of Florida. 



F. pyrurn (Dill.). 

 Pliocene. 

 ■Caloosahatchie R., Fla. 



^ 



ac 



^ 



& 





^ 



N: 



N 



A 



N 



Canal\ 



N 



Oanal 



JL 



Canal 



JL 



anat 



JL 



Canal 



[Oct., 



JL 



Table I. — The coronatum-'pyrum Sequence. 



12 3 4 



/''. coronatum Con. 

 Miocene (St. Mary's). 

 -St. Mary's River, Md. 



F. rugosum Con. 

 Miocene (St. Mary's). 

 St. Mary's River, Md. 



F. amaliculatum (L.). 

 Pleistocene. 

 ■Cornfield Harbor, Md. 



F. incile Con. 

 Miocene (yellow marl 



of Burwell Bay). 

 Burwell Bay, J a m (! s 



River, Va. 



^ 



& 



& 





^ 



N 



N 



Cana/'' 



N 



Canal 



Z^C 



JL 



Cdnal 



JL 



:^ir: 



:sL 



Canal \ 



JL 



3 



Table II. — The coroiuitum-iiin'lc Sequence. 



