Cenozoic Floras Around the Northern Pacific 6i 



Carpinus, Castanea, Cercidiphyllum, Corylus, Fagus, Ginkgo, 

 Juglans, Liquidambar, Myrica (Comptonia), Platanus, Popidus, 

 Prtinus, Quercus, Salix, Sequoia, Taxodium, Tilia, Trapa, and 

 Ulmtis. The abundance of Sequoia emphasizes the temperate 

 aspect of this flora, which with sUght modifications has been 

 recorded from several other Eocene locaHties in the Arctic in- 

 cluding Greenland and Spitzbergen. A flora of older Tertiary 

 age, collected by Mason and others" on the shore of the Bering 

 Sea south of Nome and on St. Lawrence Island, is made up of 

 Alnus, Platanus, Sequoia, and other temperate genera. 



The significance of older Tertiary floras of Siberia, together 

 with those of Manchuria, Korea, and adjacent parts of north- 

 eastern Asia, has been admirably summarized by Kryshtofo- 

 vich.^^ He concludes that nowhere in this region during the 

 Tertiary were there tropical or subtropical conditions, but that 

 as late as the Lower Miocene it was occupied by a deciduous 

 forest "composed mosdy of temperate types such as Fagus, 

 Ulmus, Alnus, Betula, Corylus, Populus, Juglans, Comptonia, 

 and Trapa'! He points out the similarity of this flora to that from 

 the Eocene of Alaska, and the marked difference between it and 

 the subtropical floras of older Tertiary age in western Europe. 

 His explanation of the cause of this difference is perhaps open 

 to question, involving as it does the supposed migration of the 

 North Pole to the northern part of the Pacific. It seems apparent 

 that the southwestern part of Eurasia, extensively submerged in 

 early Tertiary time, must have been characterized by a much 

 warmer climate than the northeastern part of this land mass, 

 far removed from the ameliorating influences of the Atlantic. 

 In any event, with the pole in its present position, the climatic 

 differences between these two parts of Eurasia are almost as 

 great today as those indicated for the Eocene. In addition to 



