E. V. Wulff —174— Historical Plant Geography 



Africa, the complete separation of these two continents taking place 

 only after the Eocene stage. At the same time, the sea separating 

 America from Africa becomes wider and wider, due to the drifting of 

 America westward. 



The connection between Africa and India through Madagascar 

 Hkewise persisted as late as the beginning of the Tertiary period, being 

 broken only in the Eocene stage due to the drifting of India north- 

 ward. This movement of India northward is confirmed, according to 

 Sahni (1936), by paleobotanical data. The Permo-Carboniferous flora 

 of southern Asia belongs to the type of Gigantopteris, i.e., it is a tropical 

 flora, while the flora of India of the same period is of the Glossopteris 

 type, undoubtedly adapted to a temperate climate. With India and 

 Asia located as at present the contiguity of these two widely different 

 floras would be entirely inexplicable. It must be presumed that India 

 at that time lay considerably farther south and was separated from 

 Asia by the Tethys Sea. Only later did India drift northward, resulting 

 in the seeming juncture of these two floras. 



At an earlier period, i.e., in the Jurassic, Australia broke away from 

 India and Ceylon and Antarctica from Africa. The latter, still retain- 

 ing connection with South America, drifted in a southeast direction. 

 Sometime during the Tertiary period Australia separated from Ant- 

 arctica, which, however, preserved until the Quaternary period its 

 connection with South America. Not until the Quaternary period, due 

 to the westward drift of the Americas, did Antarctica break away from 

 South America and drift farther and farther in the direction of the 

 South Pole. At about the same time, during the Ice Age, Greenland 

 broke away both from North America and Europe, thus causing the 

 isolation of these two continents from each other. 



From the foregoing we may conclude that the contact between 

 Europe and North America persisted until the Quaternary period, 

 between Africa and South America until the Eocene stage, between 

 Africa and India also until the Eocene stage, between Australia and 

 India until the Jurassic period, between Australia and Antarctica and 

 South America until the middle of the Tertiary period, and, lastly, 

 between Antarctica and South America until the Quaternary period. 



Du ToiT (1937) gave in his recent book on "Our Wandering Con- 

 tinents" very important geological proofs of Wegener's theory, at the 

 same time introducing some modifications. According to his view- 

 point, the continents were originally represented by two great land 

 bodies. The southern, Gondwanaland, embraced Brazil, Guiana, 

 Uruguay, Africa, Arabia, Madagascar, India, western and central 

 Australia, and Antarctica; the northern, Laurasia, included central 

 and eastern Canada, Greenland, Scandinavia, Finland, Siberia, and 

 northern China. These two great continental masses were separated 

 by the Tethys Sea. Regressions of the latter led for a short time to a 

 connection between Gondwana and Laurasia (between Africa and 

 Europe; between Indo-China and Australia). 



The breaking up of Gondwanaland, according to du Toit, took 

 place not earlier than the Cretaceous or, perhaps, the Tertiary period. 

 India began its movement to the northeast, over a distance of 1,500 

 km., at the beginning of the Cretaceous period. During the Cre- 



