From far off came a sound that, to the boys, resembled nothing so much as distant thunder. But unlike thunder, instead of ceasing, it grew steadily in volume. "Here they come!" shouted Mr. Harkness, as the advancing roar grew louder. The solid earth beneath the boys' feet seemed to shake as the stampede swept toward them. Suddenly, a mile or more off, a dark cloud grew and grew until it spread half across the blue sky, wiping it out. "They raise as much dust as a tornado," exclaimed Blinky. "Pesky critters! I'd like to get a shot at the Moquis what started them." But it was no time to exchange remarks. The face of each man in that little band was grave, and he appeared to be mustering every ounce of courage in his body for the struggle that was to come. To the boys, as to the men, the situation was clear enough. Across the plateau the stampeding cattle were thundering, headed straight for the Graveyard Cliffs. Behind them, like a mighty wall, rose the sheer face of a precipice where a bold peak of the range soared upward. Between this wall and the ominously named gorge was the little band of horsemen. They faced the problem of turning the stampede or being swept with it into the jaws of the deep, narrow gulch. Small wonder that the bravest of them felt his heart beat a little quicker as the cattle rushed on. Suddenly Mr. Harkness espied the boys. "You boys go back!" he shouted sharply. "I should never have let you come. This is too dangerous for you." "Why, dad, we'll be all right. Let us stay and see it out," protested Harry. "Go back at once, boy," said Mr. Harkness sternly. "You don't know the danger." There was no disobeying the stern command, and the boys, all of them with the exception of Tubby, regretting the necessity, turned their ponies away. The stout youth was inwardly much gratified at the idea of avoiding the stampede. "Beefsteak is all very fine," he said to himself, "but I like it inside, and not on top of me, at the bottom of a gulch." As the boys wheeled their mounts and separated from the main body of the cow-punchers, three other mounted figures swept toward them with wild yells. The newcomers were the three Simmons brothers, the recruits to the Boy Scouts. With them, and close behind, came Charley and Frank Price and Jeb Cotton. All had ridden post haste to the spot on receipt of the hastily 'phoned message from headquarters. Each boy gave the secret salute of the scouts as he drew rein, and awaited orders. A regular howl of disappointment went up when they learned that they had been ordered off "the firing line," so to speak. "It's a shame," growled Tom Simmons. "That's what," assented Jeb Cotton, trying to quiet his little calico pony, which was dancing about, scenting the excitement in the air. Indeed, all the animals seemed to have caught the infection, and were prancing about, almost unmanageable. Perhaps the increasing thunder of the hoofs of the advancing stampede had something to do with it.