6 
NEW YORK ZOOLOGICAL SOCIETY. 
Along with this close resemblance, there seemed at first to be 
also an appreciable inferiority in the size and beauty of the ani- 
mals found in America, as compared with their Old World con- 
geners. The puma and the jaguar were compared with the lion 
and tiger, somewhat to the discredit of the former, and our black 
bear, which was surprisingly numerous in Colonial times, suf- 
fered also, when compared with the brown bear of Europe ; as 
did our Virginia deer, in comparison with the European red deer. 
Later, however, when the frontier was pushed inland, and the 
grizzly, the wapiti and the moose were measured by the 
standards of the European brown bear, red deer and elk, no such 
superiority could be claimed for the Old World animals. In pro- 
fusion of distinct types, however, North America, with its bison 
and prong-horn, which, with the black-tailed deer and the wapiti, 
virtually monopolized the great prairies and plains of the West, 
could not vie with the magnificently diversified fauna of Africa, 
with its hundred and more species of bovine antelopes, to say 
nothing of other huge mammals. 
Close as is the relationship of Eurasian and North American 
mammals, it never amounts to specific identity in the view of the 
best American systematists, who differ in this respect from Euro- 
pean zoologists/ The polar bear, and one or two smaller arctic 
mammals form the sole exceptions to the above statement. 
FIRST RADIATION. 
This poverty of animal life, both as to variety and number, 
has not always existed, and a close study of the fossil mammals 
of North America, of which we have a very complete record 
from the Rocky Mountain region, demonstrates that there have 
been two separate and distinct periods of great development and 
radiation of mammals on this continent, together with several 
clearly distinguishable immigrations from other lands. The last 
of these immigrations from the Old World, by way of Behring 
Straits, gave us the predominant members of our present fauna. 
The first of these periods of development is known as the 
Puerco, and dates from the very dawn of the Basal Eocene, some 
three million years ago. Deposits of this horizon are found in 
New Mexico, and have revealed to us a large and varied fauna, 
with true mammals, some as large as a Newfoundland dog. In 
European beds of a corresponding age, the Cernaysien, a similar 
but more limited fauna is found. 
This Puerco fauna flourished and radiated, paralleling many 
