iö Art. 8. — A. Kryshtofovich : 



determined by me, so as to allow a detailed comparison with the 

 best known floras of other regions. Still, the above list shows 

 some important features, namely : — 1) scarcity of ferns and conifers' 

 2) abundance of broad-leaf plants, and 3) identity of the floras 

 found above and below the Inoceramiis horizon. The forms in the 

 list are quite foreign to the overlying Tertiary, with the exception 

 of a few ; but they show more aflinities with the inferior horizon, 

 the Gyliakian, though looking a little younger than latter. It is 

 not to be denied, that the flora in question bears a close resem- 

 blance to some of the so-called Arcto-Tertiary, and I shall put 

 the Orokkian flora in the same rank with the Patoot Bed and 

 with the Haldem and Quedhnburg in Europe ; these are mostly 

 Senonian and partly Turonian. The animal fossils, corresponding 

 to the Turonian, have not been observed in SakhaHn. The general 

 question as to the age of the so-called Arcto-Tertiary floras and their 

 relations to the Cretaceaus in general, necessitates a full revision 

 of previous materials and great care in future collections. For 

 instance, the " Tertiary " beds of Vancouver have already been 

 properly placed into the Cretaceous, though Heer (1867) tried 

 to explain, but erroneously, the apparently underlying position of 

 the really Cretaceous broad -leaved flora by means of inversion of 

 strata. Asa Geay, Gaednee, and Sapoeta long ago, as Knowlton 

 did more recently, expressed their opinion about the Eocene age 

 of the Arctic floras, which Heee treated as Miocene. 



Also Dawson, in his papers on the fossil floras of Canada, 

 persisted in lowering the ago of some of them into the Cretaceous, 

 notwithstanding Heee's objections. It is very probable that some 

 of the very typical Upper Cretaceous elements, as Platanus, Popu- 

 lus arctica and others, represented in the Orokkian, have generally 

 passed over into the Tertiary and afterwards widely spread towards 

 the south. Therefore, if not all the Arctic floras with Populus 



