GEOGRAPHICAL DEVELOPMENT OF THE AMERICAS 103 



north into Alaska and Greenland, where no such vegetation 

 is possible under present conditions. Numerous conifers were 

 mingled with the deciduous trees, but we do not find ex- 

 clusively coniferous forests. Palms, though not extending 

 into Greenland, flourished magnificently far to the north of 

 their present range. On the other hand, the Paleocene flora 

 of England points to a merely temperate climate, while that 

 of the succeeding Eocene was subtropical. 



South America. — Nothing is definitely known concerning 

 the condition of Central America and the West Indies and very 

 little as to South America. As no marine rocks of Paleocene 

 date have been found in any of these regions, it may be inferred 

 that all the existing land areas were then above the sea, and there 

 is some evidence that South America was much more extended 

 in certain directions than now. From the character and dis- 

 tribution of modern plants, fresh-water fishes, land and fresh- 

 water shells, there is strong reason to believe that in late 

 Mesozoic times a land-bridge connected Brazil with equatorial 

 Africa and this connection may have continued into the Pale- 

 ocene, though it is only fair to observe that some highly com- 

 petent authorities deny the reality of this bridge. There is 

 also evidence, though incomplete, of a connection between 

 South America and Australia by way of the Antarctic continent, 

 and it is clear that that polar region could not have had the 

 rigorous climate of the present time. In the upper part of 

 the Cretaceous, the last of the Mesozoic periods, there was 

 a possibility of migration, however indirect, between every 

 continent and every other, for the huge land reptiles called 

 Dinosaurs have been found in the non-marine Cretaceous 

 rocks of every continent, which could not have been the case, 

 had any of the great land areas been isolated. There is no 

 known reason to assume that the land-bridges were essentially 

 different in the Paleocene. 



