ON THE EXTINCT ANIMALS OF NORTH AMERICA. 
287 
period, it is true, many kinds of huge Proboscideans roamed 
over the surface of the earth ; but these differ so much from what 
we now call u elephants,” that it becomes necessary to distin- 
guish them by another name ; and that of Mastodon , first 
applied by Cuvier, is generally adopted. 
Mastodons however were, after all, very like elephants, only 
being distinguished by some peculiarities of the teeth ; and by 
means of intermediate species the two forms pass so gradually 
into one another, that it is difficult to say, in the case of some 
species, with which group they ought most properly to be 
classed. One other form of animal, which can be referred to the 
order Proboscidea , is known in the Old World — the Dinotlie- 
rium , a huge beast, the nature of which for a long time was 
very doubtful, having been grouped by some naturalists with 
the Manatees, by others even with the Marsupials. Its remains 
have been found, though comparatively rarely, in Miocene de- 
posits in Grermany, France, Greece, Asia Minor, and India. 
Here our knowledge of the history of the order Proboscidea , 
as derived from palaeontological researches in the Old World, 
ends. The Dinotherium , being in its teeth and some other 
respects slightly less specialised than the other forms, constitutes 
some kind of an approximation to the Ungulate animals, 
especially the tapirs ; but the gap to be bridged over is very 
wide ; and no remains referable to animals of the order, or any 
intermediate forms between this and other orders, have been 
found in Old World Eocene deposits. 
Let us now turn to America. Neither at the present time 
nor within the memory of man have any Proboscidean animals 
existed within the length and breadth of the whole continent. 
But at one time — and that, geologically speaking, a very recent 
one — both true elephants and true mastodons abounded in North 
America, and the last-mentioned genus extended far into the 
southern portion of the continent. The elephant, the remains of 
which are most abundant throughout what are now the United 
States, differed but very slightly, if at all, from that which at the 
same period ranged throughout the northern portion of the Old 
World from the British Isles to Alaska. The commonest species 
of mastodon ( M . Americanus , or Ohioticus , or giganteus) 
seems to have survived to a much later period than any of its 
European congeners, and even to have been the last extinct of 
all the American Proboscideans. Eemains of other elephants 
and mastodons, though not differing in any remarkable degree 
from well-known European forms, have been found in Pleistocene 
and (at all events with respect to the last-named genus) in 
Pliocene deposits ; but, as far as the evidence is at present 
before us, nowhere earlier. 
So far, then, we find that elephants and mastodons, of types 
