THE UPPER CRETACEOUS FLORAS 

 OF THE WORLD 1 



BY 



EDWARD WILBER BERRY 



Introductory 



The Upper Cretaceous was a period of world-wide transgressions of 

 the sea, in consequence of which its deposits are abundantly represented 

 on all of the continents by marine fossiliferous deposits. Invertebrate 

 paleontologists, especially those of France, have taken the lead in deter- 

 mining its subdivisions, the most prominent stratigraphic elements in 

 its faunas being aberrant Rudista 1 , both the Dibranchiate and Tetra- 

 branchiate Cephalopoda, and Micraster and other genera of Echinoidea. 



Fossil plants occupy a relatively unimportant place in the correlation 

 of the predominantly marine formations of the period. They are, never- 

 theless, much more abundant than in the Lower Cretaceous. In the 

 initial deposits of the Upper Cretaceous sea (of different age in different 

 areas) they become most important factors in correlation, as in the case of 

 the Dakota sandstone of the West, the initial deposits of the Atlantic 

 Coastal Plain, or those of Bohemia, Saxony and the Prussian Border. 



Both the lower and upper limits of the Upper Cretaceous have occa- 

 sioned prolonged discussion. Long-established usage in England and the 

 ruling of the International Geologic Congress make the Albian the 

 lowest stage of the Upper Cretaceous, and this usage is in harmony with 

 the fact that the first widespread Upper Cretaceous transgression of the 

 sea was inaugurated in the Albian. Haug (Traite, 1910) considers the 

 Albian, Cenomanian and Turonian as a separate major division which 

 he terms Mesocretaceous, and his usage has many commendable features. 



1 All references to Diatoms are omitted, as are also most scattered refer- 

 ences to marine alga?. 



