34 Dr. E. C. A^. van Hoepen 



lived under severe conditions in high northern regions, vsrould not 

 be so heavily affected, indeed, the advancing cold climatic zone 

 would only bring them a greater field for expansion. What 

 animals and plants lived in Permian times in high northern re- 

 gions? Amalitzky and Tschemyschew tell us that Pareiasaurus, 

 Dicynodon and Theriodont-like reptiles lived together in northern 

 Russia with a flora including typical members of the Glossopteris 

 flora — for example Glossopteris and Gangamopteris — in Middle 

 Permian times, or to be exact, before the deposition of the Rus- 

 sian Zechstein. The advancing cold climatic zone now came in 

 contact with a similar association, to which it offered good living 

 conditions. Had the cold zone advanced farther the remaining 

 flora and fauna would possibly also have disappeared; however, 

 its progress stopped. Then the temperature became gradually 

 higher; the ice covering of the southern continents began to melt, 

 and consequently its northern edge began to retreat southwards. 

 The cold zone adjoining mcved with it to the south and took 

 its acquired fauna and flora with it. While the Glossopteris flora 

 and the Pareiasaur fauna were moving southwards, the climate 

 of Europe became milder and a new flora and fauna was formed 

 by immigrants, by adaptations from local species, or by both. 

 As the ice edge retreated further southwards the Glossopteris 

 flora entered India, but probably there was no means for its ac- 

 companying fauna to do so too, for no remains of this fauna have 

 yet been found in India. There must have been some land con- 

 nection between Europe and Africa, for not only does the 

 Glossopteris flora occur in the African lower Permian rocks, but 

 remains of ** theriodont '*-like reptiles have been found in de- 

 posits, which are but slightly younger. Pareiasaurus came some- 

 what later. The Glossopteris flora also entered Australia from 

 the North; but its associated land fauna could not follow. 

 Whether the Glossopteris flora entered South America via North 

 America cannot be made out. No members of the Glossopteris 

 flora have been found in North America yet. There was no land 

 connection with Africa for none of the African fauna occur in 

 South America. But the land connection with North America 

 must also have been broken off for the North American fauna 

 has not passed over to South America. As the cold zone passed 



