16 



GEOLOGICAL MEMOIRS. 



5 inches 9 lines in length, 4 inches in breadth, an inch and a half in 

 thickness, and weighed 26j ounces. 



Lastly, in the town of Pozzuoli itself, when the foundations for the 

 hospital were dug in 1832 at the height of 25 feet above the sea and 

 22 feet below the present surface, 103 species were found (Enumer. 

 vol. ii. p. 270), not one of which belongs to a species either entirely or 

 locally extinct, although in this case also there was by no means an 

 identity in the condition of the sea with that which exists at present, 

 since Corbula nucleus and Diplodonta rotundata (the latter of which 

 I have never found near Naples) were far more abundant than they 

 are now, while Venus Iceta, Poli (non L.), Donax trunculus, Mytilus 

 minimus and others appear to have been less abundant than they are 

 now. 



If now we place these different localities in the order of the pro- 

 portion they exhibit between extinct and existing species, placing 

 first those places which contain the greatest number of extinct spe- 

 cies, we shall obtain them in the order of date of their deposit, since 

 we may fairly conclude that those placed at the head of our list are 

 of the earliest formation. 



Not now in the Mediter- 

 ranean. 



Now extinct. 



77 per cent. 

 53 „ 



77 per cent. 

 53 „ 



46 „ 



43 „ 



50 „ 



40 „ 



37 „ 



35 „ 



38 „ 



30 „ 



34 „ 



30 „ 



34 „ 



30 „ 



34 „ 



29 „ 



25 „ 



25 „ 



25 „ 



23 „ 



25 „ 



22 „ 



18 „ 



18 „ 



17 „ 



17 ., 



20 „ 



15 „ 



15 „ 



14 „ 



11 M 



11 „ 



10 „ 



8 M 



9 „ 



8 M 



11 », 



6 » 



5i „ 

 6 „ 



5^ „ 

 5 „ 



4 „ 



3 „ 



1 » 



If » 

 „ 



„ 



„ 



Monasterace 



Sortino 



Cotrona, Cutro, &c 



Naseti 



Lamato "Valley 



Caltagirone 



Central Sicily 



Buccheri 



Caltanissetta 



Syracuse 



Palermo 



Gravina 



Pezzo 



Messina 



Girgenti 



Militello 



Carrubbare near Reggio 



Monteleone 



Cefali near Catania 



Sciacca 



Tarento 



Nizzeti near Catania .... 



Melazzo 



Tschia 



Coast near Monte Nuovo 

 Pozzuoli ^ 



It appears therefore manifest that the passage from the tertiary 

 period to the present has been perfectly gradual, and that, without the 

 intervention of any convulsion or abrupt change, certain species have 



