154 
ORIGIN OF LIFE IN AMERICA 
other mammals apparently had their original home in this 
continent. Peccaries and tapirs, which, as we know, require 
a hot and moist climate, lived as far north as Pennsylvania 
even during the time when vast glaciers were supposed to have 
covered the whole of Canada and a substantial slice of the 
United States. We are told that the fauna of this period 
clearly reveals the state of the climate. If the remains of the 
animals above referred to indicate anything, they show us un¬ 
doubtedly that the climate was mild, with an abundance of 
vegetation and animal life. In common with most other geo¬ 
logists, Dr. Hay believes that the climate of the Glacial 
Epoch must have been cold in North America, because he 
assumes the certain existence of vast ice-masses at that time 
even in New York, in Indiana and in Missouri. If we deal 
with this climatic problem from an independent standpoint 
and endeavour to reconstruct the conditions prevailing during 
the Glacial Epoch, from purely faunistic evidence, our con¬ 
clusions cannot point to the prevalence of an exceptionally 
cold climate. Proof of the existence of a cold climate in the 
United States during the Pleistocene Period seems to be fur¬ 
nished, says Dr. Hay,* by the occurrence of the three genera 
of mammals, Rangifer, Bootherium and Symbos. 
The name Bootherium is now applied to an extinct large 
sheep-like creature, viz., B. bombifrons, whose remains have 
been discovered in Pleistocene deposits of Kentucky. Accord¬ 
ing to Dr. Kowarzik (see p. 7), Bootherium was probably 
the direct ancestor of the northern genus Ovibos, which has 
never been found in any Pleistocene beds in the United States. 
Bootherium can scarcely be claimed as an exponent of a 
cold climate, because it has never lived north of the United 
States. The latest discoveries seem to indicate that a number 
of sheep-like animals originated in the United States towards 
the latter part of the Pliocene Period, and left their remains 
in various parts of the country. Thus the extinct Eucera- 
therium, first identified by Dr. Sinclair and Mr. Furlong from 
a cave in California, and Preptoceras from another Californian 
cave, are both allied to Bootherium and Ovibos. Hence Ovibos 
is the sole member of this group which has survived, having 
Hay, O. P., “ On the Changes of Climate,” p. 372. 
