^ i s 
312 THE ORIGIN OF THE FLORA OF ATLANTIC NORTH AMERICA. 
least, had reached to the vicinity of its present habitat before the glacia- 
tion of the region. Among the fossil specimens already found in Cali- 
fornia, and which our trustworthy palzeontological botanist has not yet 
had time to examine, we may expect to find evidence of the early arrival 
of these two Redwoods upon the ground which they now, after much 
vicissitude, scantily occu 
“ Differences of climate, or circumstances of migration, or both, must 
have determined the arrival of. Sequoia upon the Pacific; and of Taxo- 
dium upon the Atlantic coast. And still the Redwoods will not stand 
in the east, nor could our Taxodium find a congenial station in Cali- 
rnia, 
seem to have been the fate of a more familiar Gymnosperous tree, the 
Ginkgo or Salisburia. It is now indigenous to Japan only. Its ancestor, 
as we may fairly call it, since according to Heer ‘ it corresponds so en- 
tirely with the living species that it can scarcely be separated from it, 
once inhabited northern Europe and the whole arctic region round to 
Alaska, and had even a representative further south iu our Rocky Moun- 
tain district. For some reason, this and Glyptostrobus survived only on 
the shores of eastern Asia. 
" Libocedrus, on the other hand, appears to have cast in its lot with the 
Sequoias. Two species, according to Heer, were with the ancient ones in 
Spitzbergen. Of the two now living, one, Z. decurrens, the incense Cedar, 
is one of the noblest associates of both the present Redwoods ; the other 
is far south in the Andes of Chili. 
deciduous trees and shrubs, which are now known by their fossil remains 
to have flourished throughout the polar regions when Greenland better 
Balsam Poplar, or Balm of Gilead tree; more Beeches than there are 
now,a Hornbeam and a Ho Hornbeam me Birches, a Persimmon, 
like our 
m Fo 
ma; 
Black Walnut ; two or three Grape Vines, one near our souther * 
Grape or Muscadine, the other near our northern Frost Grape; à P 
very like our Basswood of the Atlantic States only; a Liquidambar; ? | 
