ROCKY MOUNTAIN GOAT 
107 
possessing this vast range. Like almost all other mammals, 
the cougar (Felis concolor), which in all its essential habits 
and traits remains the same, whether living in mountain, 
open plain or forest, under arctic cold or tropical heat, has 
yet been split up into several distinct species. 
The nearest Old World relations of the cougar are the lion 
and tiger, both of which differ from it very strikingly in size, 
habit and colour. It is perfectly obvious, therefore, that it 
is not a geologically recent immigrant from Asia. Two very 
closely allied species of large cats, moreover, have been dis¬ 
covered in Pleistocene deposits in Argentina; while the 
cougar itself has left its remains, along with those of extinct 
members of the cat tribe, in the Conard Fissure. Another 
large cat (Felis hillianus) has been found fossil by Professor 
Cope in the Blanco formation of Texas, this being now looked 
upon as middle Pliocene. Hence it is probable that the 
ancestors of the cougar already flourished in North America 
as well as in the southern continent in Pliocene times. The 
facts of its recent distribution seem to point to its having 
entered North America from the south, and it may pos¬ 
sibly have done so in Pliocene times when the northern 
continent became definitely connected with South America. 
Further details as to its early history are still lacking. 
As we descend the mountains through the forest belt and 
finally reach the foot-hills, we meet with two large ungulates 
whose acquaintance we have not hitherto had an opportunity 
of making. Both of these are confined to the western States, 
and are well known to the hunters of the Rocky Mountain 
region. The black-tail, or mule deer (Odocoileus hemionus), 
as it is often called on account of its big prominent ears, 
seems at first sight not to be very different from the American 
elk or wapiti, except in size. But the latter belongs to quite 
a different genus. If we examine the antlers of the two more 
carefully, we notice that the brow tines are lacking in the 
mule deer. There are also distinctions in the skull, while 
the lower parts of the metacarpal bones of the front limbs 
are retained in the mule deer. The wapiti deer is descended 
from an Old World stock which, as I explained (p. 68), 
crossed over from Asia by a land bridge in Pliocene or early 
Pleistocene times. In it only the upper metaoarpals remain, 
