UPPER TERTIARY, OR PLIOCENE. 



221 



II. Miocene; 



or 



Medial Tertiary. 



Strata containing from 

 twenty to thirty per 

 cent, of extinct species 

 of shells. The tempe- 

 rature of the sea, as in- 

 dicated by the shells, of 

 k a sub-tropical character. 



The Crag of the ma- 

 ritime parts of Es- 

 sex, Suffolk, and 

 Norfolk. Faluns 

 of the Loire. Beds 

 in the Yal d'Arno. 



III. Eocene; 



or 



Lower Tertiary. 



\ 



/ Marine and freshwater de- 

 posits ; the recent spe- 

 cies of shells amounting 

 to scarcely more than 

 five per cent. The pre- 

 vailing forms indicate a 

 marine temperature al- 

 most equal to that of the 

 existing tropical seas. J 



The series of de- 

 posits, comprised 

 in the tertiary 

 basins of London, 

 Hampshire, Paris, 

 and the Nether- 

 lands. 



16. Upper tertiary, or pliocene. — From the large 

 proportion of recent species of shells which occur in the 

 pliocene strata, the beds have all the characters of a 

 modern aggregate, as in the extensive and beautiful col- 

 lection from Palermo before us, for which I am indebted to 

 the liberality of the Marquess of Northampton. 



They are from a range of hills, which rises to an 

 elevation of about 200 feet above the level of the Medi- 

 terranean, immediately behind Palermo. These hills are 

 in a great measure composed of coarse limestone, made up 

 of friable shells, which are frequently in an admirable 

 state of preservation ; in some examples preserving even 

 their markings and natural polish. The elegant and pic- 

 turesque manner in which they are occasionally grouped 

 renders them objects of great beauty and interest. 

 These fossils, with but few exceptions, are of species still 

 living in the adjacent sea ; a proof that when the limestone 

 was formed, the same condition of the basin of the Medi- 

 terranean existed as at present, and that it was unin- 



