Suddenly, to my utter amazement, the hoofs were jerked upward, the tails flourished in the air, and amid a cloud of dust the buffalo seemed to sink into the earth before me. One vivid impression of that instant upon my mind. I remember looking down upon the backs of several buffalo dimly visible through the dust. We had run unawares upon a ravine. At that moment I was not the most accurate judge of depth and width, but when I passed it on my return, I found it about twelve feet deep and not quite twice as wide at the bottom. It was impossible to stop; I would have done so gladly if I could; so, half sliding, half plunging, down went the little mare. I believe she came down on her knees in the loose sand at the bottom; I was pitched forward violently against her neck and nearly thrown over her head among the buffalo, who amid dust and confusion came tumbling in all around. The mare was on her feet in an instant and scrambling like a cat up the opposite side. I thought for a moment that she would have fallen back and crushed me, but with a violent effort she clambered out and gained the hard prairie above. Glancing back I saw the huge head of a bull clinging as it were by the forefeet at the edge of the dusty gulf. At length I was fairly among the buffalo. They were less densely crowded than before, and I could see nothing but bulls, who always run at the rear of the herd. As I passed amid them they would lower their heads, and turning as they ran, attempt to gore my horse; but as they were already at full speed there was no force in their onset, and as Pauline ran faster than they, they were always thrown behind her in the effort.