508 Kryshtofovich — Cretaceous Age of the 



bles the Celastrophylla of the Dakota. Sagenopteris 

 variabilis and Cocculus affinis are common in the Ceno- 

 manian of Bohemia, and Aralia tikhonovichii is repre- 

 sented there by a closely allied species. Having many 

 features common with the Cenomanian flora of Europe, 

 the Gyliakian flora is, however, more closely allied to 

 those of North America and Greenland. If in making- 

 more close comparisons with the American Cretaceous 

 floras we notice that the Gyliakian flora has some ele- 

 ments of the Patapsco flora, its resemblance with those 

 of the Dakota and Raritan is more striking. The pres- 

 ence in the Gyliakian of Populus arctica, not yet discov- 

 ered in the Atane beds or even in some younger (in 

 which, however, it was probably recorded under some 

 other names) also compels me to correlate the Gyliakian 

 with the younger rather than the older, and I am there- 

 fore inclined to regard it as the equivalent of Dakota, 

 Raritan and Atane, being Cenomanian and probably 

 partly Turonian. Thus the paradoxal presence of the 

 Nilssonia of real Mesozoic aspect in the "Mgach Flora" 

 of Heer is quite simply explained, and the botanists must 

 give up the hope of finding it still living somewhere in 

 China as was expressed by some of them on account of its 

 supposed existence as late as in the " Miocene Flora" of 

 Sakhalin. 



The flora of the Ainuan Series shows very few features 

 of resemblance either with the upper or Orokkian flora or 

 even with that of the Gyliakian Series, being represented 

 mainly by ferns, in part not yet determined. There are 

 only a few remains of a Populus of primitive aspect 

 identified by me as Populus cf. potomacensis Ward which 

 occurs in what is probably an uplifted horizon of this 

 series. I believe this flora corresponds to the Kome 

 flora of Greenland as it is not younger than Albian, but 

 the complete investigation of it is not yet made. 



The importance of correctly determining the age of the 

 Sakhalin fossil floras may be understood when it is 

 recalled that in all Asia there have not before been known 

 any upper Cretaceous floras except single remains men- 

 tioned in my introductory paragraphs and some petrified 

 specimens hardly comparable with the flora of impres- 

 sions of other countries, and presenting therefore insuf- 

 ficient materials for judging the evolution of the flora in 

 Asia. 



