372 O. C. Marsh— Vertebrate Life in America. 
can only say in summing up, that the Marsupials are clearly 
the remnants of a very ancient fauna, unas occupied this 
continent millions of years ago, and from which the other 
Mammals were doubtless all oo although the direct evi- 
dence of the transformation is wantin 
Although the Marsupials are Bee related to the still 
lower Monotremes, now living in the Australian Region, we 
supposed absence in our Miocene and Pliocene can have but 
limited weight, when taken in connection with the fact that 
they flourished in the Post-Tertiary, and are still abundant. 
The evidence we now have is quite as strongly in favor of a 
migration of Marsupials from America to the Old World, as the 
reverse, which has been supposed by some naturalists. Possi- 
bly, as Huxley has suggested, both countries were peopled with 
these low mammals from a continent -now submerge 
_The Edentate mammals have long been a puzzle to to zoolo- 
ocene, while Moropus, the oldest Edentate genus, is found in 
the middle Miocene, and one species in the lower Pliocene. 
The Edentates have been usually regarded as an American 
type, but the few living forms in Africa, and the Tertiary 
species in Europe, the oldest known, have made the land 
of their nativity uncertain. I have already given you some 
Saget ot pe that the Edentates had their first home 
taken place in the Miocene period, as the Isthmus of Darien 
was then submerged; but near the close of the Tertiary, 
the elevation of this region left a much broader strip of land 
than now exists there, and over this, the Edentates and other 
