We may take it for granted that, before the coming of the white man, the mountain sheep ranged over a very large portion of western America, from the Arctic Ocean down into Mexico. Wherever the country was adapted to them, there they were found. Absence of suitable food, and sometimes the presence of animals not agreeable to them, may have left certain areas without the sheep, but for the most part these animals no doubt existed from the eastern limit of their range clear to the Pacific. There were sheep on the plains and in the mountains; those inhabiting the plains when alarmed sought shelter in the rough bad lands that border so many rivers, or on the tall buttes that rise from the prairies, or in the small volcanic uplifts which, in the north, stretch far out eastward from the Rocky Mountains. While some hunters believe that the wild sheep were driven from their former habitat on the plains and in the foothills by the advent of civilized man, the opinion of the best naturalists is the reverse of this. They believe that over the whole plains country, except in a few localities where they still remain, the sheep have been exterminated, and this is probably what has happened. Thus Dr. C. Hart Merriam writes me: "I do not believe that the plains sheep have been driven to the mountains at all, but that they have been exterminated over the greater part of their former range. In other words, that the form or sub-species inhabiting the plains (_auduboni_) is now extinct over the greater part of its range, occurring only in the localities mentioned by you. The sheep of the mountains always lived there, and, in my opinion, has received no accession from the plains. In other words, to my mind it is not a case of changed habit, but a case of extermination over large areas. The same I believe to be true in the case of elk and many other animals." That this is true of the elk--and within my own recollection--is certainly the fact. In the early days of my western travel, elk were reasonably abundant over the whole plains as far east as within 120 miles of the city of Omaha on the Missouri River, north to the Canadian boundary line--and far beyond--and south at least to the Indian Territory. From all this great area as far west as the Rocky Mountains they have disappeared, not by any emigration to other localities, but by absolute extermination. A few years ago we knew but one species of mountain sheep, the common bighorn of the West, but with the opening of new territories and their invasion by white men, more and more specimens of the bighorn have come into the hands of naturalists, with the result that a number of new forms have been described covering territory from Alaska to Mexico. These forms, with the localities from which the types have come, are as follows: _Ovis canadensis_, interior of western Canada. (Mountains of Alberta.) _Ovis canadensis auduboni_, Bad Lands of South Dakota. (Between the White and Cheyenne rivers.)