Ch. XVIII.] 
PARIS BASIN. 
255 
some districts where lakes and rivers then existed, and to the 
site of some of the lands encircling those lakes, and to the 
position of a, great bay of the sea, into which their surplus 
waters were discharged. We can also show, as we shall en- 
deavour to explain in the next chapter, the points where some 
volcanic eruptions took place. We have acquired much in- 
formation respecting the quadrupeds which inhabited the land 
at that period, and concerning the reptiles, fishes, and testacea 
which swarmed in the waters of lakes and rivers ; and we have 
a collection of the marine Eocene shells more complete than has 
yet been obtained from any existing sea of equal extent in 
Europe. Nor are the contemporary fossil plants altogether 
unknown to us, which, like the animals, are of extinct species, 
and indicate a warmer climate than that now prevailing in the 
same latitudes. 
When we reflect on the tranquil state of the earth implied 
by some of the lacustrine and marine deposits of this age, and 
consider the fullness of all the different classes of the animal 
kingdom, as deduced from the study of the fossil remains, we 
are naturally led to conclude, that the earth was at that period 
in a perfectly settled state, and already fitted for the habitation 
of man. 
The heat of European latitudes during the Eocene period 
does not seem to have been superior if equal to that now ex- 
perienced between the tropics ; some living species of mol- 
luscous animals both of the land, the lake, and the sea, existed 
when the strata of the Paris basin were formed, and the con- 
trast in the organization of the various tribes of Eocene 
animals when compared to those now co-existing with man, 
although striking, is not, perhaps, so great as between the 
living Australian and European types. At the same time we 
are fully aware that we cannot reason with any confidence on 
the capability of our own or any other contemporary species to 
exist under circumstances so different as those which might 
be caused by an entirely new distribution of land and sea ; 
and we know that in the earlier tertiary periods the physical 
