LATEIi CRETACEOUS AND KAINOZOIC. 193 



Moamian 20 species* 



(Lower greensand and Speeton clay, Wealden 

 and Hastings sands, Kootanie and Queen 

 Charlotte groups of Canada.) 



Thus we have a great and sudden inswarming of the 

 higher plants of modern types at the close of the Lower 

 Cretaceous. In relation to this, Saporta, one of the most 

 enthusiastic of evolutionists, is struck by this phenome- 

 non of the sudden appearance of so many forms, and 

 some of them the most highly differentiated of dicotyle- 

 donous plants. The early stages of their evolution may, 

 he thinks, have been obscure and as yet unobserved, or 

 they may have taken place in some separate region, or 

 mother country as yet undiscovered, or they may have 

 been produced by a rapid and unusual multiplication of 

 flower-haunting insects ! Or it is even conceivable that 

 the apparently sudden elevation of plants may have been 

 due to causes still unknown. This last seems, indeed, 

 the only certain inference in the case, since, as Saporta 

 proceeds to say in conclusion : "Whatever hypothesis 

 one may prefer, the fact of the rapid multiplication of 

 dicotyledons, and of their simultaneous appearance in 

 a great number of places in the northern hemisphere at 

 the beginning of the Cenomanian epoch, cannot be dis- 

 puted." f 



The leaves described by Heer, from the Middle Cre- 

 taceous of Greenland, are those of a poplar (P. primmva). 

 Those which I have described from a corresponding hori- 

 zon in the Eocky Mountains are a StercuUtes {S. vetus- 

 tula), probably allied to the mallows, and an elongated 

 leaf, Laurophyllum (L. crassinerve) (Fig. 69), which 

 may, however, have belonged to a willow rather than a 

 laurel. These are certainly older than the Dakota group 



* Including an estimate of Fontaine's iindescribed species. 

 + "Monde des Plantes," p. 197. 



