188 E. C. Andrews — The Geological History of the 



been distributed over the earth during land connections prior 

 to the Cretaceous Period. The discussion of their distribu- 

 tion in this connection, therefore, would be liable to result 

 in confusion. 



Tho distribution of the mammals, however, specially the 

 placentals, may be taken as independent testimony in the 

 discussion of the distribution of the flowering plants. 



The accompanying notes are abbreviations from Chamberlin 

 and Salisbury's Geology (vol. Ill, 1906). 



Marsupials and monotremes appear to have been in existence 

 in the Upper Cretaceous. The earliest actual records of the 

 placentals are from the early Tertiary. Among them were 

 undifferentiated sloths, rodents, lemurs, edentates, and carni- 

 vores. Before the close of the Eocene, the Ungulata, Carni- 

 vora, Edentata, Insectivora, Rodentia, Quadrumana, Cetacea, 

 and Sirenia, were distinctly defined. 



Oligocene. Wo living genera recorded. 



Miocene. Still no living genera, unless some doubtful Canis 

 and allied types be allowed. 



Pliocene. Many strange genera, but there were also many 

 modern genera in existence. 



Pleistocene. Many extinct genera, but also very many mod- 

 ern genera, in existence. 



In the chapters on the Tropical, the African, the South 

 American, and the ]NTew Zealand problems, it will be seen how 

 valuable is the testimony of these independent witnesses, the 

 mammals. 



V. The Development of the Australian Angiosperms. 



If, now, the data supplied in the foregoing chapters be cor- 

 rect, it is permissible, perhaps, to suggest along which lines the 

 population of Australia by angiosperms has moved. In this 

 connection it must be remembered that, vast as is the number 

 of species existing still in Australasia, the mere existence of 

 types such as Casnarina, Fagus, Epacris, Phih/drum, StacJc- 

 housia, Pleurocarpcea, Tetratlieca, Eucalyptus, Angophora, 

 Brunonia, and many others, implies a wholesale extinction of 

 genera and species, intermediate between these types and their 

 nearest living allies. 



For the sake of simplicity, the problem may be considered 

 under six heads, namely, The Tropical Problem, the South 

 African Problem, the South American Problem, the [Northern 

 Hemisphere Problem, the ISTew Zealand Problem, and the West 

 and East Australian Problem. 



