CONCLUSIONS 
231 
ones came direct from Europe. Professor Suess,* on the 
other hand, favours a north Atlantic land connection in high 
latitudes between Greenland, Iceland and Scotland, and he 
thinks its origin dates back to the beginning of the Miocene 
period. Considering that there is such unanimity in favour 
of some kind of land bridge between the Old World and the 
New at this time, it is strange that Professor Schuchertf 
should entirely isolate North America in his palaeogeographi- 
cal maps from the Old World, not only in Miocene, but even 
in Pliocene times. 
Although the Pliocene fauna, according to Professor 
Osborn (p. 81), is as yet only imperfectly and sparsely 
known, being characterised by hosts of southern invaders 
which now flood the continent, a direct land bridge between 
North America and the Eurasiatic continent must likewise 
have existed, unless we assume that the mighty elephant 
Tetrabelodon (Dibelodon) which is represented by several 
species in the New World, reached North America by way 
of South America. Whether the still existing more hardy 
stock of Asiatic immigrants came to North America towards 
the end of Pliocene, as I argued in a previous chapter 
(p. 97), or during Pleistocene times, is a question which had 
not hitherto, I think, been seriously debated. That their pre¬ 
sence in North America is due to a wide land bridge across 
Bering Strait (see Fig. 7) seems to me evident. 
In this very brief survey of the past faunas of North 
America I have endeavoured to show that an important centre 
of evolution and dispersal existed in western North America 
in the past, just as it exists to a lesser degree at the present 
day. The strong faunistic affinity between western North 
America and western Europe, which we can still trace at this 
moment among many of the invertebrates and lower verte¬ 
brates of the two areas, seems to be the outcome of an ancient 
direct geographical communion between these land-masses. 
Certain features in mammalian palaeontology appear to 
strengthen my views, which are primarily based on a study 
of the modern fauna. In the succeeding chapters I shall 
bring forward further evidence showing that North America 
* Suess, E., “ Antlitz der Erde,” Yol. III. 2 , p. 765. 
t Schuchert, C., “ Puleogeography,” PI. 98—100. 
