V.] 



THE TERTIARY EPOCH. 55 



there are many shells exclusively confined to the Miocene 

 period. We have already stated, that in Touraine and in 

 the South of France near Bordeaux, in Piedmont, in the 

 basin of Vienna, and other localities, these Miocene formations 

 are largely developed, and their relative position has been 

 shown in diagrams Nos. 3 and 4, letter e, chapter II. 



Eocene period. The period next antecedent we shall call 

 Eocene, from MS, aurora, and xouvof, recens, because the ex- 

 tremely small proportion of living species contained in these 

 strata, indicates what may be considered the first commence- 

 ment, or dawn, of the existing state of the animate creation. 

 To this era the formations first called tertiary, of the Paris and 

 London basins, are referrible. Their position is shown in the 

 diagrams Nos. 3 and 4, letter d, in the second chapter. 



The total number of fossil shells of this period already known, 

 is one thousand two hundred and thirty-eight, of which num- 

 ber forty-two only are living species, being nearly in the pro- 

 portion of threejindyj L half jn j onjg , Jmndr^d . Of fossil species, 

 not known as recent, forty-two are common to the Eocene and 

 Miocene epochs. In the Paris basin alone, 1122 species have 

 been found fossil, of which thirty-eight only are still living. 



The geographical distribution of those recent species which 

 are found fossil in formations of such high antiquity as those 

 of the Paris and London basins, is a subject of the highest 

 interest. 



It will be seen by reference to the tables, that in the more 

 modern formations, where so large a proportion of the fossil 

 shells belong to species still living, they also belong, for the 

 most part, to species now inhabiting the seas immediately ad- 

 joining the countries where they occur fossil ; whereas the 

 recent species, found in the older tertiary strata, are frequently 

 inhabitants of distant latitudes, and usually of warmer climates. 

 Of the forty-two Eocene species, which occur fossil in England, 

 France, and Belgium, and which are still living, about half 

 now inhabit within, or near the tropics, and almost all the rest 

 are denizens of the more southern parts of Europe. If some 



