ORTMANN : TERTIARY INVERTEBRATES. 317 



Although in our map Antarctica has been drawn as a continental mass, 

 we have mentioned above that it was at certain times possibly broken 

 up into archipelagoes. Antarctica may have been a continent once, but 

 it is hard to say at what time. We may safely say and all authors ex- 

 cept Forbes agree in this that it existed about the close of the Cretaceous 

 and the beginning of Tertiary time, but we do not know anything beyond 

 that. In this respect it is interesting to see what evidence is furnished by 

 the geological configuration of southern Patagonia. Through Mr. Hatcher 

 and others we know that the Cretaceous ends with a series of deposits, 

 called Guaranitic beds (see Hatcher, 1900 a, p. 93), which indicate a gen- 

 eral upheaval of the land. After the deposits of these beds the respective 

 parts were land, and no deposits were formed till the beginning of Oligo- 

 cene times (Magellanian beds). From this time on we have a slow subsi- 

 dence, which reaches its maximum in Patagonian time (lower Miocene), 

 and then follows, in Santacruzian time (upper Miocene): another upheaval, 

 which culminated, possibly, in the final formation of the Cordilleras at the 

 close of the Miocene. Within these general movements, there were a 

 number of smaller oscillations, for instance like that indicated by the 

 Upper Lignites (Hatcher, 1900 a, p. 99). It is beyond the scope of this 

 report to go more into detail ; but we may say here that the geology of 

 southern Patagonia points to a maximum extent of land at the end of 

 Secondary time and during the Eocene, and to a large if not maximum 

 extent of water during lower Miocene time. If it is permitted to draw 

 any conclusions from this, we should put the largest extent of Antarctica 

 at the end of the Cretaceous and in the Eocene, while a marked, if not 

 final, interruption was brought about in the lower Miocene. Within this 

 time, smaller, and more or less important oscillatory movements took place. 



This refers, however, only to the history of the Antarctic continent in 

 the first part of the Tertiary period. In Cretaceous times similar move- 

 ments may have taken place, so that the connection of Antarctica with the 

 present continents (or parts of them) may have been established and 

 destroyed repeatedly. And indeed v. Ihering (1894, pp. 405 and 425) 

 dates some connections of America and Australia with Antarctica far 

 back in Mesozoic times. (Compare v. Ihering's Mesozoic " Archinotis," 



1893. P- 9-) 

 And further, the above refers only to South America. It is not at all 



necessary that the connection between Antarctica and the Austral lands 



