—these remnants of a past multitudinous vegeta¬ 
tion,—ever since they were allowed to exist and 
perpetuate their kind, have been obliged to wage 
war upon neighbors from generation to generation, 
in order to gain or retain a foothold, resorting to 
changes of ground, of character, or weapons, in 
order to win in the incessant battle of life. 
PROOFS OF DOUBFK MIGRATION. 
That the plants have made the double journey 
described is plainly proved by the characters of 
alpine plants on high peaks of the North Temper¬ 
ate Zone. They are found to be identical with 
Arctic plants. Now they could not have passed 
from northern regions directly to these summits 
during the southern flight, for the reason that both 
Arctic regions and these mountain tops were being 
slowly covered simultaneously, with snow, soon 
becoming permanent ice. Manifestly cold-loving 
plants—our Alpine plants—could ascend mountains 
only when fleeing from torrid heat, and exactly 
that condition was experienced on the return 
journey; so here on all the peaks of the North 
Temperate Zone are stranded Arctic species of 
plants, with less northern families established 
on the slopes of the mountains. 
GREAT FOREST OF THE NORTHWEST. 
It has been stated that Europe and Asia were 
deprived of their quota of plants by the many long 
transverse ranges of mountains ’ preventing the 
passing of plants north or south, except through 
the wide gaps between ranges; wdiile North Amer- 
