30 
ORIGIN OF LIFE IN AMERICA 
Labrador fauna is largely composed of indigenous American 
species, which have not penetrated to Greenland. This seems 
to suggest that the points of resemblance in the fauna of 
Labrador and Greenland may have been more marked in 
remoter times, before the influence of the continental fauna 
had impressed itself upon the outlying peninsula of Labrador. 
Considering the extreme probability of Labrador having been 
connected by land with Europe by way of Greenland and 
Iceland in Pliocene times, we might expect some Euro¬ 
pean mammalian types to have occurred in north-eastern 
North America. The little evidence we possess tends to 
show that the mammalian life of the extreme north of 
western Europe was always poor. We cannot assume 
that insurmountable barriers prevented European mammals 
from invading America, because certain species such as the 
reindeer and lemming seem to have passed from America to 
Europe across a North Atlantic land bridge. It might be 
argued that European animals did cross over, but were unable 
to maintain themselves in America, a fate which has largely 
befallen the American immigrants in Europe. For such a 
supposition, however, we still lack evidence. If no examples 
of European animals or plants were known from the American 
side of the water, we might assume the land bridge to have 
been a discontinuous one, as Mr. Hedley suggested to me, 
connecting Greenland alternately with Labrador and Scotland. 
But one of our strongest supports for the North Atlantic 
land bridge is, as I said, the presence of the European 
Helix hortensis in North America. It still occurs in 
Labrador. From Labrador it travelled southward along the 
coast. Is it possible that the whole strip of coast was at 
that time cut off by some barrier from the interior of 
North America ? 
Supposing the western parts of the Labrador plateau had 
become covered by glaciers as soon as the North Atlantic land 
bridge was formed, it might have produced an effectual barrier 
against western invaders and yet have allowed eastern forms 
to reach Labrador. 
Later on I intend to return to this problem again. Mean¬ 
while, let us journey westward across the high plateau of 
Labrador towards Hudson Bay and Central Canada. As we 
