lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



TERTIARY 



Tertiary plants from the Arctic have heen encountered at very 

 many localities, usually associated with coal. This, and plants with 

 their roots in place as in the case of Equisetum in Spitzbers^en ; the 

 association with fresh water mollusks, as in Greenland ; or aquatic 

 beetles, as in Spitzbergen and Iceland ; as also the presence of fresh 

 water diatoms in the matrix and the mixtures of branches and delicate 

 foliage, prove conclusively that these Arctic floras and the associated 

 coals cannot represent drift material from lower latitudes as some 

 have supposed.' 



The similarity in facies and their mode of occurrence, as well 

 as the similar petrographic character of the intimately associated 

 basalts suggest that all of these Tertiary Arctic floras are essentially 

 similar in age, although it is clear that in Spitzbergen, Alaska and 

 probably elsewhere, more than a single horizon is represented. Heer, 

 the pioneer in this field, called them Miocene, just as Lesquereux 

 called the Fort Union and Wilcox floras Miocene, but the Arctic Ter- 

 tiary floras are certainly older than Miocene and younger than Ft. 

 Union. This is indicated by the determination of the so-called Kenai 

 flora of Alaska as of upper Eocene age, and if any one of them is 

 proved to be upper Eocene none of the others can be older than 

 middle Eocene or younger than Oligocene. Collateral evidence of their 

 age is furnished by the age of the greatest extension of subtropical 

 floras into the Temperate Zone, which is in upper Eocene (Jackson) 

 to middle Oligocene (Vicksburg) time. 



Plants or coal of Tertiary age are found at the numerous widely 

 distributed localities shown on the accompanying sketch map (fig. 4). 

 These completely encircle the pole and reach to within 83° of it 

 (Grinnell Land). These will be treated at greater length than the 

 older floras because in some cases they are more extensive and also 

 because they consist very largely of species belonging to existing 

 genera, and hence can be discussed more intelligently than the older 

 floras. 



It may be well at the start to dispose of an oft quoted assertion, 

 as for instance " most of Heer's determinations were based upon 

 leaves, which give no data for generic identification " (Gregory, op. 

 cit., p. 413). I would readily admit that much of Heer's material was 

 fragmentary, that he was over sanguine in some of his determinations, 



^ Gregory makes much of this idea, which as we liave seen is easily disproved. 

 Gregory, J. W., Congres Geol. Intern. Compte rendu Xcme Session Mexico, 

 1906, p. 413, 1907. 



