A. Gray—Forest Geography and Archeology. 193 
waters the cast leaves, fruits, and occasionally branches, which 
are imbedded in what are called Miocene Tertiary or later 
eposits, most abundant in Europe, from which the American 
character of the vegetation of the period is inferred. Geologists 
give the same name to these beds, in Greenland and Southern 
when Greenland probably had very nearly the climate which 
it has now. 
Wherefore the high, and not the low, latitudes must be 
assumed as the birth-place of our present flora;* and the present 
arctic vegetation is best regarded as a derivative of the temperate. 
This flora, which when cireumpolar was as nearly homogeneous 
round the high latitudes as the arctic vegetation is now, when 
slowly translated into lower latitudes, would preserve its homo- 
geneousness enough to account for the actual distribution of the 
same and similar species round the world, and for the original 
endowment of Europe with what we now call American types. 
It would also vary or be selected from by the increasing differ- 
entiation of climate in the divergent continents, and on their 
different sides, in a way which might well account for the 
present diversification. From an early period, the system of 
sides, there are re-siftings to take into the account. The 
Glacial period or refrigeration from the north, which at its in- 
ae er paleontology nor the study of arctic sedimentary strata afford 
any evidence of it. Or if they were any, it was too remote in time to concern the 
Present question 
