In the old days the prongbuck was found as soon as the westward-moving traveller left the green bottom-lands of the Mississippi, and from thence across to the dry, open valleys of California, and northward to Canada and southward into Mexico. It has everywhere been gradually thinned out, and has vanished altogether from what were formerly the extreme easterly and westerly limits of its range. The rates of extermination of the different kinds of big game have been very unequal in different localities. Each kind of big game has had its own peculiar habitat in which it throve best, and each has also been found more or less plentifully in other regions where the circumstances were less favorable; and in these comparatively unfavorable regions it early tends to disappear before the advance of man. In consequence, where the ranges of the different game animals overlap and are intertwined, one will disappear first in one locality, and another will disappear first where the conditions are different. Thus the whitetail deer had thrust forward along the very narrow river bottoms into the domain of the mule-deer and the prongbuck among the foothills of the Rocky Mountains, and in these places it was exterminated from the narrow strips which it inhabited long before the mule-deer vanished from the high hills, or the prongbuck from the great open plains. But along great portions of the Missouri there are plenty of whitetails yet left in the river bottoms, while the mule-deer that once dwelt in the broken hills behind them, and the prongbuck which lived on the prairie just back of these bluffs, have both disappeared. In the same way the mule-deer and the prongbuck are often found almost intermingled through large regions in which plains, hills, and mountains alternate. If such a region is mainly mountainous, but contains a few valleys and table-lands, the prongbuck is sure to vanish from the latter before the mule-deer vanishes from the broken country. But if the region is one primarily of plains, with here and there rows of rocky hills in which the mule-deer is found, the latter is killed off long before the prongbuck can be hunted out of the great open stretches. The same is true of the pronghorn and the wapiti. The size and value of the wapiti make it an object of eager persecution on the part of hunters. But as it can live in the forest-clad fastnesses of the Rockies, into which settlement does not go, it outlasts over great regions the pronghorn, whose abode is easily penetrated by sheep and cattle men. Under anything like even conditions, however, the prongbuck, of course, outlasts the wapiti. This was the case on the Little Missouri. On that stream the bighorn also outlasted the wapiti. In 1881 wapiti were still much more plentiful than bighorns. Within the next decade they had almost totally disappeared, while the bighorn was still to be found; I shot one and saw others in 1893, at which time I had not