400 ANNUM, REPORT SMITHSONIAN INSTITUTION, 1918. 



the earlier Mesozoie, about whose floras nothing is known, and these 

 may have witnessed the evolution of the angiosperms. They cer- 

 tainly originated in one of the land masses of the Northern Hemis- 

 phere, and the evidence points to the vast expanse of Asia or the 

 Arctic region as the theater of their earlier evolution. Certainly 

 during the Upper Cretaceous there was a continuous spreading 

 southward in Europe, North America, and Asia along land routes 

 that are known from independent lines of evidence to have been in 

 existence at that time, and almost everywhere the same forms occur, 

 alike in Bohemia, Alabama, or Sachalin Island. They penetrated 

 far into South America during the Upper Cretaceous (Argentina), 



Fig. 38. — Oleichenia pulcliella Knowlton, from the Upper Cretaceous of Wyoming (after Knowlton). 



and even reached Antarctica (Graham Land). These Upper Cre- 

 taceous floras invariably show a mingling of temperate and tropical 

 types indicative of a humid warm temperate climate, And they always 

 contain forms like Dammara, Araucaria, Widdringtonites, Pro- 

 teaceae, Myrtaceae, etc., that are to-day largely confined to anti- 

 podean regions. Throughout the Upper Cretaceous, new types con- 

 tinued to appear, while the stragglers from older floras gradually 

 were dying out, so that by the dawn of the Tertiary most of the 

 archaic forms had become extinct. 1 



1 A full account of the Upper Cretaceous floras of the world with lists of species and a 

 complete bibliography is given by Berry in the volumes on the Upper Cretaceous pub- 

 lished in 1916 by the Maryland Geological Survey. 



