LATER CRETACEOUS AND KAINOZOIC. 



199 



leaves, known as Credneria, found in the Cenomanian of 

 Europe, and those called Protophyllum (Fig. 72) in 

 America, appear to be nearer to the plane-trees than to 

 any others, though representing an extinct type. The 

 laurels are represented in this age, and the American 

 genus Sassafras, which has now only one species, has not 

 one merely but several species in the Cretaceous. Dios- 

 pyros, the persimmon-tree, was also a Cretaceous genus. 



FIG. 72. Protopliyllum boreale, Dawson, reduced. Upper Cretaceous, 

 Canada. 



The single species of the beautiful Liriodendron, or tulip- 

 tree, is a remnant of a genus which had several Cretaceous 

 species (Figs. 74, 75). The magnolias, still well repre- 

 sented in the American flora, were equally plentiful in the 

 Cretaceous (Fig. 73). The walnut family were well repre- 

 sented by species of Juglans (butternut) and Carya, or 

 hickory. In all, no less than forty-eight genera are pres- 

 ent belonging to at least twenty-five families, running 

 through the whole range of the dicotyledonous exogens. 

 This is a remarkable result, indicating a sudden profusion 



