316 RECORDS. 



changes in world geography, and is regarded as a working 

 hypothesis, based on our present knowledge of geology, palaeon- 

 tology and zoology, especial consideration being given to the 

 mammalian palaeontology. 



The former extension of the Antarctic continent, so as to 

 join Australia with South America, is regarded as occurring at 

 the end of the Cretaceous period and is represented in the first 

 map of the series. The connection with South Africa is regarded 

 as too problematic to place on the map. The Eocene map 

 shows the extreme of Tertiary submergence of the continents, 

 which are represented as forming six isolated land masses. The 

 three northern continents are connected throughout the Oligo- 

 cene, Miocene, Pliocene, and Pleistocene, Africa being joined to 

 them by the Miocene, South America by the Pliocene epoch. 

 The Pleistocene map shows especially the simultaneous glacia- 

 tion of both northern and southern regions, modified in the north 

 by sinking of the old Arctic continent beneath the sea-level. 



The supposed ancient continents of Lemuria, Atlantis, the 

 Brazil -African land bridge, etc., are regarded either as proposed 

 on insufficient data or outside the limits of this series. 



In general it has been found possible to consider the true 

 ocean basins (limited by the 1,000-foot contour) as permanent 

 through Tertiary time. The union of Antarctica with Australia 

 and South America is an exception to this rule, but is based on 

 a large amount of evidence. It appears probable also that the 

 disturbed belt which stretches through central Europe to south- 

 central Asia, and ends perhaps in the East Indian islands, has 

 been, in part, raised from abyssal depths to an equally stupen- 

 dous height above the sea, since the beginning of the Tertiary. 



Discussion. — Professor Osborn emphasized the value of these 

 maps as expressing working hypotheses for the use of students 

 of vertebrate palaeontology. 



Dr. Julien called attention to the evidences of glaciation in 

 South Africa as having a bearing upon the question of a previ- 

 ous existence of land masses further south. 



Edmund Otis Hovev, 



Secretary. 



