GEOLOGICAL MEMOIRS. 



The following species were common during the two periods :• 



Cardium echinatuin. 



tuberculatum. 



edule. 



papillosum. 

 Pectunculus violascens. 

 Nucula margaritacea. 

 Pecten Jacobaeus. 



opercularis. 



varius. 

 Natica millepunctata. 



Trochus conulus. 



crenulatus. 



rugosus. 



magus. 

 Turritella communis. 

 Cerithium vulgatum. 



lima. 

 Buccinum mutabile. 

 Dentalium dentalis. 



entalis. 



The following were common during the tertiary period, but are 

 now rare or extinct : — 



Solen coarctatus. 

 Psammobia feroensis. 

 Diplodonta rotundata. 

 Lucina radula. 

 Venus radiata. 



vetula. 

 Pectunculus minutus. 

 Natica sordida. 

 Trochus crispus. 



Trochus millegranus. 

 Fusus rostratus. 

 Pleurotoma dimidiatum, &c. 

 Murex vaginatus. 

 Buccinum semistriatum. 

 Marginella aurioulata. 

 Dentalium striatum. 



elephantinum. 



strangulatum. 



The following are now abundant, but either did not exist, or were 

 extremely rare during the tertiary period. The species marked with 

 an asterisk in the succeeding list are not known in a fossil state : — 



Pholas dactyl us. 

 Solen legumen. 

 Mactra stultorum. 

 *Pandora flexuosa. 

 Psammobia florida. 

 Tellina planata. 



tenuis. 

 Lucina lactea. 

 Donax trunculus. 



semistriata. 



venusta. 



complanata. 

 Venus gallina. 



decussata. 



*geographica. 



*laeta, Poll. 

 Cardita calyculata. 



trapezia. 

 Chama gryphoides. 

 Modiola barbata. 

 Mytilus minimus. 

 Lima inflata. 



squamosa. 

 Pecten hyalinus. 

 Spondylus gaederopus. 

 Patella scutellaris, Blainv. 



caerulea, L. 



tarentina, O. 

 Gadinia Garnoti. 



*Fissurella rosea. 



gibba. 

 Bulla striata. 

 *Rissoa violacea. 



*auriscalpium. 



*fulva. 

 Haliotis tuberculata. 

 *Ianthina bicolor. 



*nitens. 

 *Trochus granulatus. 



fragarioides. 



fanulum. 



canaliculatus. 



Kichardi. 



Adansoni. 



umbilicaris. 

 *Turbo neritoides, L. 

 Pleurotoma purpureum. 



*taeniatum, &c. 

 Fasciolaria lignaria. 

 Tritonium nodiferum. 



*cutaceum. 

 Buccinum variabile. 



Pusio. 



d'Orbignyi. 

 Columbella rustica. 

 *Cypr8ea lurida. 



rufa. 



*pulex. 



Concerning these, we may remark that the most abundant, as 



