FOSSIL FLORA OF ALASKA. 587 



PliyUites arctica, Knowlton. 

 Knowlton, Pi-oc. U. S. Nat. IMus., vol. xvii, 1S94, p. 230, pi. ix, figs. 10, 11. 



Herendeen bay ; Charles H. Townsend. 



Discussion of the Flora. 



The fossil flora of Alaska as presented in this paper embraces 115 forms. Of this 

 number, one is regarded as extra-limital and three are interglacial, being found also 

 living about Muir glacier. Of the 111 forms remaining, no less than 46 are peculiar 

 to Alaska, leaving ()4 forms having an outside distribution. On removing the nine 

 species found at cape Lisburn about which there is little question of age, we have 

 remaining only 55 species, or a little less than fifty per cent, from which to deter- 

 mine the bearing of the plants on the question of age. 



An examination of the distribution gives the following numerical results : The 

 Laramie has three species, of which one is doubtful ; the post-Laramie beds of Col- 

 orado have 10 species ; the Livingston beds of jNIontana six species ; the Fort Union 

 beds 16 species, of which one is doubtful ; the Green river group nine species, of 

 which three are in doubt ; the Mackenzie river deposits 11 species ; British Colum- 

 bia has seven species in the INIiocene and four in the Laramie, with two common to 

 both ; California, represented by the auriferous gravels and allied formations, has 

 17 species, of which three are in dou])t; the Eocene (Alum bay, etc) six species ; 

 the Greenland Miocene, as represented at Disco island, Atanekerdluk, etc, has 29 

 species ; the Miocene of Spitzbergen 20 species ; the island of Sachalin (Siberia) 23 

 species ; Sinigalia (Italy) 12 species ; the so-called BalticMiocene 13 species ; CEnin- 

 gen 20 species ; Oligocene 11 species ; Miocene 33 species ; Pliocene 15 species. 



By combining a number of the above localities which may be legitimately takeu 

 together, still more impressive results are obtained. Thus, by combining the post- 

 Laramie beds of Colorado with the Livingston beds of Montana, 13 species are 

 found to be common to Alaska. The union of the Mackenzie river and Fort 

 Union depostts gives 2L species common to Alaska, while Greenland, Sj^itzbergen , 

 and Sachalin have no less than 39 species out of the 55 species from Alaska. This 

 last result shows, if any dependence is to be placed on fossil plants, that the floras 

 of Alaska, Greenland, Spitzbergen and the island of Sachalin are so closely re- 

 lated as to lead to the unavoidable conclusion that tliey grew under similar condi- 

 tions and were synchronously deposited. The localities enumerated show that 

 the circiimpolar flora at that time was practically similar and continuous. 



The coal-bearing beds of southeastern Alaska, to which Dall has given the name 

 Kenai group, are i)erhaps l^est exhibited on the shores of Kachekmak bay, Kenai 

 peninsula, and Cook inlet. They a])pear, however, to be widely spread over Brit- 

 ish Columbia and over the coast of Alaska and its neighboring islands. Accord- 

 ing to Dall * the sequence of the rocks, when undisturbed, appears to be, in de- 

 scending order, as follows : 



1. Soil and Pleistocene beds. 



2. Brown Miocene sandstone, with marine shells, cetacean bones and water-worn teredo-bored 

 fossil wood. (Astoria group, Niilato sandstones, Crepidula bed.) 



3. Beds of conglomerate, brown and iron-stained, alternating with gravelly and sandy layers, the 

 finer beds containing fossil leaves of Sequoia and other vegotahle remains. (Kenai group, Unga 

 beds.) 



* Bull. U. S. Geol. Survey, no. 84, 1892, pp. 232-233. 



