38 THE OX TRIBE. 



their return from the Columbia, or Oregon River, in 

 July of that year, the first Bison they saw was on the 

 day after they commenced their descent of the Rocky 

 Mountains towards the east. On the second day after 

 that, they saw immense herds of them on the banks of 

 the Medicine River. One collection of these animals 

 which they subsequently saw, on the borders of the 

 Missouri River, they estimated as being at least 20,000 

 in number. 



In 1823 it was discovered that the Bisons had crossed 

 the Rocky Mountains, and some were to be seen in 

 the vallies to the west of that range. 



East of that range of mountains, these animals migrate 

 from the uplands or mountains to the plains, and from 

 north to south, about the beginning of November; and 

 return from the south to the north, and from the plains 

 to the uplands, soon after the disappearance of the snow 

 in the spring. 



The herds of Bisons wander over the country in search 

 of food, usually led by a bull remarkable for strength and 

 fierceness. While feeding, they are often scattered over 

 a great extent of country ; but when they move, they 

 form a dense and almost impenetrable column, which, 

 when once in motion, is scarcely to be impeded. Their 

 line of march is seldom interrupted, even by considerable 

 rivers, across which they swim, without fear or hesitation, 

 nearly in the order in which they traverse the plains. 

 The Bisons which frequent the woody parts of the 

 country form smaller herds than those which roam over 

 the plains, but are said to be individually of a greater 

 size. 



The rutting takes place the latter part of July and 



