EARLY MAN IN AMERICA. 345 
Atlantic, at a time when the hands of the geological clock pointed to the same 
hour over the greater part of the world. The story of early man in America is a 
part of the greater story of the first appearance of man on the earth, so far as he 
has yet been revealed by modern discovery. 
Before we enter into these questions, we must define clearly what is meant by 
the geological clock. *>);**** 
The change in life has been so regular, definite, and orderly in the geological 
past, that it enables us to classify the rocks over the whole world into Primary, 
Secondary, and Tertiary groups. In the last of these, the higher types of Mam- 
malia become more and more specialized as we draw nearer to the frontiers of 
history; and their pedigrees, when traced from one period to another, assume the 
shape of genealogical trees, such as that which Professor Marsh has discovered 
for the horse. The living orders first appear in the Eocene, the living genera in 
the Miocene, a few living species in the Pliocene, while nearly all the living 
species come into the Pleistocene division. Again, in the interval dividing the 
last from the Historic period, the domestic animals appear and the cultivated 
fruits, and this — the Prehistoric — gradually passes into the period embraced by 
the written records. The succession of events may be used as the figures on our 
dial-plate, marking the lapse of geological time in the Tertiary period, as fol- 
lows : (i). The Eocene period, in which the placental mammals now on the 
earth were represented by extinct allied forms belonging to existing families and 
orders. The order Primates, to which man belongs, is represented by creatures 
allied to the lemurs both in the Old and New World. (2). The Miocene, in 
which the alliance between living and extinct mammals is more close, and living 
genera appear. The Primates are represented by a higher division, the family of 
apes, in Europe and in the United States. (3). The Pliocene, in which, for the 
first time, living mammalian species appear; but they are few in number compared 
with the extinct species. (4). The Pleistocene, in which the living species are 
more abundant than the extinct among the Mammalia, and the Primates are 
represented by their highest development, the family of man. (5). The Pre- 
historic, characterized by the present fauna and flora, being in possession of the 
regions in which they have been known historically. Man has increased and 
multiplied on the earth, and is possessed of domesticated animals and cultivated 
fruits, and has acquired the arts of spinning, weaving, mining, and pottery-mak- 
ing in the Old World, and gradually passed through the Neolithic, Bronze and 
Iron stages of civilization. (6). The Historic, or period covered by written 
records, which varies in each country, going back to 4000 B. C. in Egypt, and 
in America to the time of Christopher Columbus. Were the extinct species 
taken into account, it would be seen that they fill up the interval separating one 
living form from another, and that they approximate to living species as they 
approach nearer to the present time. 
It will be seen from the examination of the above periods that the inquiry 
into the antiquity of man is limited to the last four. The most highly specialized 
form in the animal kingdom cannot be looked for until the lower animals by 
