"Shoot the confounded horse; he'll kick him to death," yelled George Dumont in his ear, at the same time frantically pushing a cartridge into the empty breech of his own gun; but just then the horse swerved and fled down the hill towards the waggons. The bull, meanwhile, seeing his enemy at his mercy, had paused just for a moment as though to take breath; and now, with his nose to the ground, was making a wild dash towards him. Coke pulled up, took good aim, and fired; but unluckily, the bullet which was meant for the bison's shoulder caught him on the frontlet, his most hopelessly invulnerable part. The three younger Dumonts, unaware of the accident, were now over the brow and out of sight. George had almost pulled his trigger, when the Pawnee who had been riding near him galloped between him and the bull. The little Indian horse, more used to climbing than the heavily-built hacks of the white men, shot up the slope like a chamois, and, joining his whinny to the rider's howl, flew between the prostrate man and the bull. Fred, who had been too unnerved for the moment to do anything but try feebly to roll away out of danger, was conscious suddenly of a good deal of clattering close to him; then, looking up, he saw that the bull had turned to flee and that the shaft of an arrow was protruding from his ribs. The bull was struggling up the hill, too startled and confused to attempt to battle with his new assailant, who, in hot pursuit, was sending a second arrow after the first. "No, no; hang it; let the redskin finish him," said Dumont as Coke made ready to fire again. The bull did not require much more "finishing." Already the Indian had wounded him in two places and was getting a third arrow ready for him; and the final rush up-hill, together with loss of blood, was weakening him at every step. The mustang, not to be outraced, was soon abreast of him; and one more arrow from the persevering Indian brought the luckless beast on to his knees. Mr. Coke and his friend saw and shot a good many bisons after that, but never again one that so nearly turned their trip into a tragedy. CHAPTER XV HOW THE YO-SEMITE VALLEY WAS DISCOVERED Till 1851, the peaks and valleys of the Californian Sierra Nevada were known only as a grim, mysterious region that white men, who valued their lives, would do well not to pry into. Parties of diggers travelling westwards had crossed the range in certain places, but even the strongest bands of them carried their lives in their hands in so doing, for the Snake Indians regarded the whole neighbourhood as their special property. All that was definitely known was that, between the hills, lay deep, uninviting valleys, walled and overhung with granite blocks. The deepest and most picturesque of these, the Yo-Semite, was the great stronghold of the Indian banditti; a cunningly hidden natural fortress whose approaches no stranger would suspect; and it was only by sheer accident that white men ever discovered it.