i6 
THE LIVING WORLD. 
less signally, while the disappearance of vast bodies of water in one place and 
their reappearance in another would certainly be followed by pronounced changes 
of climate. This fact, taken in connection with the many fossil remains 
examined, prove that a tropical temperature once prevailed in the highest 
latitudes. In Greenland we find fossil remains of tropical plants and animals, 
while Northern Siberia yields innumerable evidences that over its now barren 
and ice-covered shores and plains once roamed vast herds of such equatorial 
animals as the elephant, rhinoceros and hippopotamus, which were probably 
destroyed by a sudden change of temperature during what is called the Glacial 
Period, about which, however, little is definitely known. 
The fossil remains which we find most plentiful are those of marine species, 
because of their greater numbers and more regular deposition at the bottom of 
FOSSII, remains of the earliest species of mollusks. 
the sea. Those which are most commonly met 
are given in this work, include 
" Shells. 
Corals and sponges. 
Radiated animals, star fishes 
Bodies belonging I Reptiles, saurian species. 
to the sea. | Fishes of great variety. 
Whales. 
Lobsters, crabs, mollusks. 
Water plants. 
with, and of which illustrations 
ammonites, sea urchins, etc. 
Bodies belonging 
to the land. 
Fresh-water shells. 
Garden snail. 
Quadrupeds. 
- Reptiles, several varieties, of monster size. 
Birds. 
Insects. 
_ Trees. 
