6o R' W. Chaney 



recorded by plants in the Cenozoic era, and the only migration 

 of importance in that direction until the Pleistocene or Recent, 

 when the coniferous forest was shifted from southern to central 

 and northern California."'" 



The study of the Eocene floras of Washington has not yet ad- 

 vanced to a point where a list of the families and genera repre- 

 sented can be given. Although numerous species represented in 

 the states to the south are included, indicating that the north- 

 ward movement above mentioned extended into this state, the 

 leaves are for the most part characterized by smaller size, thinner 

 texture, and more commonly serrate margins. It seems clear that 

 they represent a less tropical assemblage than do those of Oregon 

 and California and that their modern equivalents will be found 

 in temperate rain forests of higher latitudes. The same conclu- 

 sion may be reached concerning the Eocene floras from the 

 Rocky Mountain province to the east. As now described, these 

 floras include a large list of temperate genera such as Acer, 

 Alnus, Betula, Cornus, Fraxinus, Populus, and Ulmus, along 

 with subtropical types. Although many of the generic references 

 must be revised before the lists of names can be depended upon 

 as an indication of the nature of these floras, a survey of the 

 average size, margins, and texture of the leaves as figured indi- 

 cates that they represent a more temperate assemblage than those 

 along the Pacific Coast at the same latitudes. This may be ex- 

 plained as resulting from the more continental type of climate 

 in the Rocky Mountain province as compared to that of the 

 Pacific border states. 



The Kenai flora of Alaska, considered by HoUick and others 

 to be of Eocene age, includes such genera as Diospyros, Ficus, 

 and Magnolia; but the most conspicuous and widespread ele- 

 ment of this flora comprises such genera as Acer, Alnus, Betula, 



