AFFINITIES OF NORTH AND SOUTH 
245 
New World was the same then as it is now, and that Central 
and South America had already been evolved in anything like 
the present outlines. As I shall endeavour to demonstrate 
later on, South America did not then exist as a distinct great 
continent. A large land-mass evidently lay in the neigh¬ 
bourhood of the existing State of Brazil and another further 
south. And as far as we know, the southern land-mass was 
the original home of the edentates. Between it and Central 
America on the site of the present South American continent 
there were one or more broad marine channels, or oceans, as 
we might call them. And yet the edentates succeeded in 
attaining North America. I do not now wish to discuss my 
reasons for the supposition that western Mexico was then 
united by a direct land bridge with Chile. I only mention it 
in order to indicate that the appearance of edentates in the 
Eocene of North America does not afford a proof of the ex¬ 
istence of Central America at that time, nor during the 
Miocene Period. 
Professor Osborn, as I mentioned before, indicates the 
nature of the land connection between North and South 
America in the dawn of the Tertiary Era on a map which he 
kindly allowed me to copy (Fig. 21). However, he expresses 
the belief that already in early Eocene times, that is to say 
almost before the appearance of the above-mentioned arma¬ 
dillo in North America, the land bridge had ceased to exist. 
We are too apt, I think, to look upon South America as exclu¬ 
sively the home of edentates, forgetting that many other mam¬ 
mals may have originated there too. We may not all agree 
with Dr. Ameghino * in attaching the importance he does 
to that continent as a source of the Tertiary mammalia, 
but I believe we possess other evidences of a faunistic inter¬ 
change between Chile and Patagonia on the one hand, and 
western North America on the other, during the ages that 
passed between the Lower Eocene and the Miocene. 
In southern Africa we meet with a group of small blind 
subterranean creatures, the golden moles (Chrysochloridae) 
which are among the most primitive mammals in existence. 
They are quite confined at present to South Africa. But 
Ameghino, FI. “ South America, the Source of Mammalia.” 
