184 ' E. C. Andrews — The Geological History of the 



Leaves alone, especially if mixed up with certain Melaleuca 

 leaves. 



It seems peculiar also, if it be assumed that a great and 

 vigorous genus like Quercus (250 species) once flourished in 

 Australia, that some trace of it should not exist now, as the 

 climate of Tasmania and Southeastern Australia is adapted to 

 its growth, or at least that it made no xerophytic response to 

 its environment in much the same way as it has done in 

 America. 



IV. General Geographical Conditions. Transport of Plants 

 and Distribution of Mammals. 



(a) Cretaceous and Post-Cretaceous Geography and Climate. 



The accompanying notes on the general geographical condi- 

 tions of the world are abbreviations from Vol. Ill of Ckamber- 

 lin and Salisbury's Geology. In the lower Cretaceous there 

 was a general sea transgression and very little diversity in 

 the world's climate so far as can be gathered from a study of 

 the fossils. Newberry 5 suggests that in the upper beds, the 

 angiosperms belong to familiar genera such as Sassafras, 

 Laurus and Eucalyptus. 



In the Upper Cretaceous there was a very great sea trans- 

 gression in America (both North and South), Europe, Asia, 

 and Australia, and doubtless in Africa, the climate appears to 

 have been mild and warm, and is supposed by Neumayr 6 to 

 have been comparable with that of Malayasia at the present 

 time. Angiosperms were in marked ascendency. 



Eocene. Mild climate as told by fossils. Large epiconti- 

 nental seas. 



Miocene. Great terrestrial aggradation. Great terrestrial 

 degradation also. Floras become more suggestive of temperate 

 climates. Deciduous trees make their appearance. 



Pliocene. Differentiation of climate and heralding of the 

 approaching Glacial Period. 



Pleistocene. Great Glacial Periods and repeated revivals 



of glaciation. Lowering of temperature simultaneously over 



the globe. Interglacial periods. Great increase of land area 



since the Cretaceous, Eocene, Miocene, and even Pliocene 



Periods with development of deserts, high mountains, and 



marked zoning of climate. 



'United States Geol. Survey, Monograph XXVI, p. 23, 1895. 

 6 Erdegeschichte, vol. ii, p. 383. 



