330 A. Hollick — Kenai Flora of Alaska. 



not be represented in our living flora. Nevertheless, so far as 

 the paleontolbgie record indicates, they apparently disappeared 

 from the southern and central parts of the North American 

 continent in the Tertiary period and were almost exterminated 

 in similar European latitudes at the same time, but continued 

 to exist in northwestern America and northeastern Asia, until 

 their descendants were in part exterminated and the remainder 

 driven southward by the advancing cold of the Quaternary 

 period to where they are now growing. 



Their present range of distribution in the New World is 

 between northern Mexico and Bolivia, which affords an approxi- 

 mate indication of the possible extremes of climatic conditions 

 which might have prevailed in Alaska at the time when this 

 flora was growing there. The climate could not have been 

 colder than that of northern Mexico or southern California at 

 the present time, if the cycads are to be regarded as adequate 

 climatic indicators - , nor could it have been much warmer, if the 

 associated angiosperm genera are to be regarded in the same 

 light. The logical inference is, therefore, that the climate 

 which was synchronous with this Alaskan flora was about the 

 same as that of southern California and Florida at the present 

 day. We may also be warranted, apparently, in assuming that, 

 at the time when this flora flourished, either the climate of the 

 northern Pacific region was warmer than that which prevailed 

 in the mid-continental areas farther to the south, or else that 

 their meteorological conditions were not identical, thus giving 

 rise to floral differences similar to those which prevail at the 

 present day in the coastal and interior regions of the West. 



Finally, the identity of the Tertiary floras of northwestern 

 America and northeastern Asia is confirmatory evidence of a 

 former land connection between the two continents in recent 

 geologic times, which is so strongly indicated by the well recog- 

 nized physiographic and topographic features.* 



* See "The Probable Tertiary Land Connection between Asia and North 

 America," Adolph Knopf. Univ. Calif. Pub., Ball. Dept. Geol., v, 413- 

 420, 1910. 



