238 FOSSIL FLORA OF ALASKA— KNOWLTON. vol. xvii. 



the discussion of the table, that the fossil flora of Alaska is inseparably 

 connected with that of the Disco Island and Atanekerdluk beds 

 of Greenland and the so-called Arctic Miocene of Spitzbergen and 

 Sachalin. Whatever is decided, concerning them nnist apply with 

 equal force to Alaska. 



Mr. J. Starkie Gardner appears to have been the first to question the 

 Miocene age of the Greenland beds,* or rather of the Arctic floras in 

 general. The sequence of British Eocene floras is almost unbroken, 

 and in studying them and their relations to the Miocene flora he was 

 lead to important conclusions. He says: 



There is no great break iu passing from one to the other (Eocene to Miocene) when 

 we compare them over many latitudes, and but little change beyond that brought 

 about by altered temperature or migration. But if Tertiary floras of different ages 

 are met with in one area, great changes on the contrary are seen, and these are 

 mainly due to progressive modifications in climate and to altered distribution of 

 laud. Impreceptibly, too, the tropical members of the flora disappeared; that is to 

 say, they migrated, for most of their types, I think, actually survive at the present 

 day, many but slightly altered. Then the subtropical members decreased, and the 

 temperate forms, never quite absent even in the Middle Eocenes, preponderated. 

 As decreasing temperature drove the tropical forms south, the more northern must 

 have pressed more closely upon them. The Northern Eoceue, or the temperate floras 

 of that period, must have pushed, from their homo in the far north, more aud more 

 south as climates chilled, and at last, in the Miocene time, occupied our latitudes. 

 The relative prepondorence of these elements, I believe, will assist iu determining 

 the age of Tertiary deposits in Enropemore than any minute comparisons of species. 

 Thus it is useless to seek in the Arctic regions for Eocene floras, as we know them 

 in our latitudes, for during the Tertiary period the climatic conditions of the earth 

 did not permit their growth there. Arctic floras of temperate, and therefore Mio- 

 cene, aspect are in all probability of Eocene age. and what has been recognized as a 

 newer or Miocene facies is due to their having been first studied in Europe iu lati- 

 tudes which only became fitted for them in Miocene times. 



This change of view as to the age of the so-called Arctic Miocene, as 

 proposed by Gardner, has already received considerable confirmation 

 from American paleobotanists, and while it can hardly be regarded as 

 settled, it may be accepted as extremely probable. 



Dr. J. S. Newberry, in one of his latest publications, said:+ 



I called the Fort Union Group Miocene because I identified it with the plant- 

 bearing beds of Mackenzie River, Disco Island, Greenland, etc., of which the flora 

 had been studied by Prof. Oswald Heer and was by him called Miocene. This flora, 

 to which I shall ayain refer, has since been shown by Mr. .7. Staikie Gardner to be 

 Eocene. The Fort Union flora has many species iu common with the Eoceue beds of 

 the Island of Mull, Bourenemouth, etc., and holds undoul)tedly the same position. 



On this same point Sir William Dawson says:^ 



I have, also, while writing* out the above notes for jmblication, received the paper 

 of the same author (dlardner) on the Eocene beds of Ardtun, in Mull, and am fully 

 confirmed thereby in the opinion derived frcmi the papers of the Duke of Argyll and 

 the late Prof. E. Forbes that the Mull beds very closely correspond in age with the 



* British Eocene Flora, Part i, 1879, p. 8. 



t Trans. N. Y. Acad. Sci. vol. ix, p. 1 of reprint. 



I Trans. Boy. Soc. Canada, 1887, p. 36, 



