" Miocene Flora" of Sakhalin. 509 



The Cretaceous flora now discovered in Sakhalin 

 becomes still more remarkable if we remember that its 

 upper horizon shows associated with the flora a rich 

 fauna which can be correlated not only with those of 

 Hokkaido but even with the more distant fauna of Hin- 

 dustan and Vancouver. On the other hand the flora 

 itself, representing a considerable interval of time, fills 

 the gap hitherto existing between Europe and America in 

 the ring of the floras around the North Pole, the supposed 

 center of origin and migration of the Angiosperm flora. 



When completely elaborated the Mesozoic flora of Sak- 

 halin, since it is extensive and its upper limit is fixed in 

 age by the associated fauna, may furnish a helpful scale 

 for the revision of age of the Arctic floras and those of 

 Canada, on account of presence in the Orokkian of such 

 species as Populus arctica, Hedera mcclurii, etc., believed 

 to be Tertiary in the above mentioned floras. In addition 

 there are numerous floras scattered all over the vast 

 Siberian expanse and hitherto without a good scale for 

 the judging of their age. Already after a preliminary 

 study of the Sakhalin flora I decidedly put into the rank 

 of the Cretaceous the flora of Simonova 11 as being 

 older than the uppermost horizon of this system. Still 

 younger but undoubtedly Cretaceous appear some floras 

 in Amurland partly described previously as Tertiary. 

 One of the latter, namely the flora of Boguchan mountain 

 near Sagibova on Amur river, I put into the Cretaceous 

 in 1916. Others may represent the transitional floras 

 corresponding to the Laramie of western North America. 

 On the other hand, the true Tertiary flora of Sakhalin is 

 rich in species and also represents several horizons. 

 Freed from the unfortunately admixed Cretaceous ele- 

 ments it also may be taken as a good scale for com- 

 parison with the Siberian floras, especially on account 

 of the intercalation of the flora of the Dui series in Sak- 

 halin with several faunal horizons. Some interesting 

 deductions, may also result from the comparison of the 

 Sakhalin floras with those of Japan. 



The following diagram represents the relation of the 

 Sakhalin Cretaceous floras to those best known in the Old 

 and New World: 12 



u Heer, 1878, Beitrage zur foss. Flora Sibiriens mid des Amurlandes, 

 Fl. foss. Arctica, vol. 5, part 2. 



12 American and European correlations taken from Berry, E. W., Lower 

 and Upper Cretaceous floras of the World, 1911 and 1916. 



