48 Windliausen — The Cretaceous-Tertiary 



foreign provinces prevent a closer fixing of its strati- 

 graphic position at the base of the Tertiary. Affinity 

 with Brazil cannot be maintained as v. Ihering proved. 

 Neither can we find relations to the Chilian Tertiary; 

 while there Patagonian and Parana Formation have their 

 respective equivalents in the Navidad and Coquimbo 

 Beds, we do not know any marine deposits in Chile that 

 could be correlated with the San Jorge. The relations to 

 Madagascar, which have been emphazised by Ame- 

 ghino 11T and v. Ihering 11 s from the point of view of the 

 Cretaceous age to the San Jorge, are of too general a 

 character. The Eocene sediments as well as the forma- 

 tions of the Cretaceous-Tertiary boundary of Madagascar 

 are still very imperfectly known. 



Consequently, there only remain the comparisons with 

 Australia and New Zealand, which have been emphasized 

 by Ortmann and v. Ihering with special reference to the 

 Patagonian Formation. But it is not possible to build 

 up on these resemblances a stratigraphic division of a 

 European kind. Marshall 119 in his chapter on the 

 Oamaru-System of New Zealand points out in the first 

 place the great difference of individual opinions. Fur- 

 ther, he calls attention to the difficulties that crop up, 

 when the molluscan fauna of such a remote region is 

 compared with the well-limited periods of the European 

 time table in order to establish homotasial relations. 

 Just the same difficulties are met with in determining the 

 age of South American mammalian faunas, the evolution 

 of which has been influenced by a long lasting isolation. 



A lower limit in the determination of the age of the 

 San Jorge is afforded by the close of the great trans- 

 gression in the Upper Senonian. The regression of the 

 Upper Senonian sea was caused by the movements that 

 led to the breaking down of the ancient Brazilo-Ethiopian 

 (Grondwana) Continent, although some remains of it 

 lasted until the end of the Miocene. 120 These movements 

 were manifested in an orogenetic sense by the first fold- 

 ing of the Cordillera, in an epirogenetic sense by the 

 formation of the South Atlantic basin and the posthu- 

 mous reopening of the great graben-like depression 



117 Les formations sedimentaires, p. 511. 



118 Les mollusques f ossiles, p. 58. 



119 New Zealand and adjacent Islands, Handbuch der Begionalen Geologie, 

 7, 1, Heidelberg, 1911. 



120 Compare what has been said about ' ' Arehhelenis ' ' in Parts I and 

 III. 



