402 
ORIGIN OF LIFE IN AMERICA 
at that time must have had a direct land connection with 
western North America almost independently of the rest of 
South America (Fig. 14). At a still earlier stage there was 
even a more marked affinity between Patagonia and south¬ 
western North America ; and from this Professor Osborn con¬ 
cluded that the northern and southern continents were con¬ 
nected by land. But the points of resemblance are not alone 
with Patagonia and south-western North America. Professor 
Gaudry * expressed his astonishment at the striking faunistic 
relationship between the Patagonian Notostylops fauna on the 
one hand, and the faunas of the Torrejon in New Mexico and 
Cerney in France on the other. That a land bridge, discon¬ 
nected at certain intervals, extended between western North 
America and southern Europe I have urged again and again 
in the preceding chapters ; and it should be borne in mind 
how, even in these remote times, special facilities existed for 
the passage of species from Europe to the extreme south of 
South America, which no doubt were taken advantage of by 
several groups then inhabiting the Old World. 
Until recently it was thought that North and South America 
could have had no land connection subsequently to these early 
events until the end of the Miocene or the beginning of the 
Pliocene Periods. Professor Osborn, f however, has shown 
that there is now evidence for the existence of true edentates 
of the Megalonyx type in the Mascall beds of Oregon, which 
are of Middle Miocene age. During the Miocene Period 
Central America in its present shape had not yet come into 
existence. Hence we may assume that even in Miocene times 
there was a land connection between western North America 
and some portion of South America by means of a route 
which, as I argued, lay to the west of that continent. 
The rodents of the Santa Cruz fauna, as previously men¬ 
tioned, all belong to the section Hystricomorpha. They are 
very closely allied, according to Professor Scott, to recent 
South American genera. Yet all are extinct and many of 
them have left no successors. Nevertheless, though the Santa 
Cruz rodents are more primitive, the skull structure is nearly 
* Gaudry, A., “Fossiles de Patagonie,” p. 105. 
t Osborn, H. F., “ The Age of Mammals,” p. 289. 
