Editorial Comment. 253 
wholly to a time before the accumulation of the North Ameri- 
can ice-sheet, which reached both east and west beyond the 
present coast lines. But it has been ascertained that this north- 
ern part of our continent was then elevated 3,000 to 5,000 feet 
higher than now. During the epoch of ice accumvTlation and 
culmination, its boundaries probably failed to reach generally 
to the coast line of that time. Along the sea border, where 
food supplies such as savages rely upon are most easily ob- 
tained, preglacial and Glacial man may have freely advanced 
on a land margin skirting the inland ice, as along the present 
borders of Greenland. It was only in the Champlain epoch, 
closing the Glacial period, that the ice-burdened lands sank to 
their present altitude or lower, bring'ing the edges of the ice- 
sheet beneath the encroaching sea. 
The many divergent branches of the American peoples and 
their remarkable progress toward civilization in Mexico, Cen- 
tral America, and Peru, before the discovery by Columbus, in- 
dicate for this division of mankind probably almost as great 
antiquity as in the eastern hemisphere. Although we are un- 
able to define the date, in thousands of years of antiquity, when 
the American race came into its heritage, we may paradoxically 
say that it came here before it had been differentiated from the 
primordial stock of mankind so as to be racially distinct. 
Processes of change, whether of progress or of regression 
and sometimes extinction, are now taking place and are modi- 
fying species and races perhaps as fast as during any former 
period in the history of our globe. We see allied varieties or 
races of plants and animals, living intermingled in the same 
district, or more frequently in different but adjoining regions, 
or sometimes quite separated geographically, which are not 
yet sufficiently distinct to rank as separate species, but which 
seem surely destined to diverge more, until their increasing 
difference and decreasing affinity shall give them that more dis- 
tant relationship. The parent stock and the diverging branches 
are all the while represented by multitudes of individuals. Di- 
vergent species and races, therefore, have come into their 
present strongly contrasted characters from preceding ancestry 
which was a unity in its specific character, but which resem- 
bled any vigorous species of the present time in comprising a 
vast number of individuals occupying a somewhat extensive 
geographic area. 
