Ch. 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 oW, aurora, and xatvor, recens, because the ex- 
tremely small proportion of living species contained in these 
strata, indicates what may be considered the first commence- 
ment, or daivn, 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 three and a half in one hundred. 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 
