every old specimen. Often a thickness of half an inch is gone from the upper half of each horn on its outside curve, at which point the horn is worn quite flat. This is well illustrated in the horns shown in the accompanying plate, fig. 6.
Mr. Catlin[1] affords some very interesting and valuable information in regard to the bison's propensity for wollowing in mud, and also the origin of the u fairy circles," which have caused so much speculation amongst travelers:
"In the heat of summer, these huge animals, which no doubt suffer very much with the great profusion of their long and shaggy hair, or fur, often graze on the low grounds of the prairies, where there is a little stagnant water lying amongst the grass, and the ground underneath being saturated with it, is soft, into which the enormous built lowered down upon one knee, will plunge his horns, and at last his head, driving up the earth, and soon making an excavation in the ground into which the water filters from amongst the grass, forming for him in a few moments a cool and comfortable bath, into which he plunges like a hog in his mire.
"In this delectable laver he throws himself flat upon his side, and forcing himself violently around, with his horns and his huge hump on his shoulders presented to the sides, he ploughs up the ground by his rotary motion, sinking himself deeper and deeper in the ground, continually enlarging his pool, in which he at length becomes nearly immersed, and the water and mud about him mixed into a complete mortar, which changes his color and drips in streams from every part of him as he rises up upon his feet, a hideous monster of mud and ugliness, too frightful and too eccentric to be described!
"It is generally the leader of the herd that takes upon him to make this excavation, and if not (but another one opens the ground), the leader (who is conqueror) marches forward, and driving the other from it plunges himself into it; and, having cooled his sides and changed his color to a walking mass of mud and mortar, he stands in the pool until inclination induces him to step out and give place to the next in command who stands ready, and another, and another, who advance forward in their turns to enjoy the luxury of the wallow, until the whole baud (sometimes a hundred or more) will pass through it in turn,[2] each one throwing his body around in a similar manner and each one adding a little to the dimensions of the pool, while he carries away in his hair an equal share of the clay, which dries to a gray or whitish color and gradually falls off. By this operation, which is done perhaps in the space of half an hour, a circular excavation of fifteen or twenty feet in diameter and two feet in depth is completed and left for the water to run into, which soon fills it to the level of the ground.
