On the Cretaceoiis Flora of Russian Sakhalin. 23 



Jbibö^^ and mentioned by him in 1892, without any description, 

 there is in Japan one rich Cretaceous flora of the Ryöseki Series 

 (Neocomian), containing plant leaves, described by Yokoyama."^ 

 The Upper Cretaceous flora from Hokkaido, treated by Stopes and 

 Fuji,^^ sliows a peculiar state of preservation (petrification) and 

 thus could not be compared with the flora of »Sakhahn, which is 

 represented by impression of leaves ; though leaves of Dicotyledons 

 and of Nllssonia too have been also ol^served in Hokkaido. Some 

 fossil woods from Hokkaido have been described by Eeiss/^ Be- 

 sides, I am of opinion, that the flora of the Lower Division of the 

 fresh-water series in the province of Ishikari, which contains 

 Nllssonia, may also be compared with the Upper Cretaceous flora 

 of Sakhalin. 



According to the ancient view that Nilssonia may be a 

 member of the Tertiary, as in Sakhalin, there was no objection 

 to put the Series of Ishikari into the Tertiary, especially when 

 we consider the affinity of its flora with the " Tertiary " of Green- 

 land. However, in the present stage of our knowledge about the 

 true origin of Nilssonia and its complete absence everywhere in 

 the Tertiary, I am also inclined to put the iV//sso/?/a-bearing bed 

 of Ishikari into the Cretaceous. The absence of sharp demarca- 

 tion between the Cretaceous and fresh-water Supra-Cretaceous of 

 Hokkaido probably corresponds to a similar relation in Sakhalin 

 between the Upper Cretaceous and the Dui series to the south of 

 Cape de la Jonquière, though some fossihferous beds may be 

 discovered in Hokkaido corresponding to the non-fossiliferous con- 

 glomerate of Dui-Rogatyi. It is necessary to make a special study 

 of the age, to establish it as either true Tertiary or Laramie, of 

 the Upper division of the Fresh-water series, from which some 



1) JiMBÖ (192), p. 29. 2) YoKOTAMA (1894). 3) Stopes and Fura (1909) ; id. (1910). 

 4) Eelss (1907). 



