576 



STRATIGRAPHICAL GEOLOGY 



an assemblage which resembles that now found in the Carribean Sea 

 more than that of the existing Lusitanian and Mediterranean 

 provinces, and the same is the case with the Echinoderm fauna. 



Among Lamellibranchs the prevalent genera were Area, Lucina, 

 Tivela (Grateloupia}, Tellina, Cardita, and Ostrea. Of Gastropods 



Fig. 192. GROUP OF MIOCENE FOSSILS (natural size). 



a. Cassidea saburon. c. Area barbata. 



b. A*t.6'4a glandiformis. d. Ostrea crassissima (youn j). 

 mon e ' Clypeaster altecostatus. 



there is aN mos ^ t variety, the chief genera being Conus, Fusus, 

 Melongena, :. u lella, Murex, Cassidaria, Pleurotoma, Oliva, Ancilla, 

 Turritella, Potamides, Cerithium. The only known representatives 

 of the tetrabranchiate Cephalopoda are the generas Nautilus and 

 Aturia ; the dibranchiate order is represented by Spirulirostra. 



