On the Cretaceous Flora of Russian Sakhalin. ^O 



creasing the ashes. The old assumption, that the quality of 

 Sakhalin coals depends only on the degree of tectonic disturbances, 

 and not on the age, is of a limited significance, although the 

 Cretaceous coals are generally much influenced by such move- 

 ments. 



Those coals in Sakhalin which were formerly regarded as 

 Tertiary and possessing very different characters, may be separated 

 now into two groups of quite different ages, Tertiary and Cretace- 

 ous. From these two groups the Cretaceous coals are quite 

 uniform, on the other hand, the Tertiary coals look now also not 

 so varied in quality. 



In contrast to most of the Cretaceous coals, the lowermost 

 coals of the Tertiary Dui Series are of an exceptional good quality ; 

 thus possibly a good coal could be found either in the uppermost 

 Cretaceous or in the transition to the overlying Tertiaries. 



V. Summary. 



From all that has been said above, the following conclusions 

 may be drawn : 



1. In the study of the Sakhalin flora, Heee had unfortunately 

 only mixed collections to rely upon. Though his Dui Flora was 

 almost purely Tertiary, a considerable part of his Mgach Flora was 

 truly Cretaceous. 



2. The really mesozoic form Nilssonia must be excluded from 

 the Tertiary flora. 



3. Below the formerly described sole representative of the 

 Cretaceous, namely the Senonian, we have now to add deposits of 

 considerable thickness, belonging to the Turonian, Cenomanian and 

 probably also still lower horizons. 



4. All the Cretaceous in liussian Sakhalin, so far known, 

 will be subdivided into the three Series : Orokkian, Gyliakian and 



