"Couldn't be any sheep herders coming so soon, to turn their nibblers on our land; could it?" Dick wanted to know. He spoke of "our land," for he and his brother owned a small ranch in partnership with Bud. "No, I don't reckon it was the sheep herders themselves," said Slim, "but it might be some of their bunch coming to size things up. The government never made a worse mistake than to throw this Indian land open to everybody. Them fellers at Washington should have barred the sheep men!" To hear Slim talk you would have imagined that he could go to Washington and regulate matters all by himself. But if you understand the feeling of western cattle men and horse men against sheep herders it will make it easier to comprehend. "Well, if any of 'em try to come to Happy Valley," said Bud, "they'll wish they'd stayed out." "That's right!" chimed in Nort and Dick. Suddenly one of the cowboys on the outer fringe of the riding posse uttered a low cry and exclaimed: "There they are--off to the left!" As he spoke the moon came out from behind ragged clouds and disclosed two horsemen riding at full speed across the prairie. "After 'em, fellows!" cried Slim, and he fired some shots in the air. The boy ranchers put spurs to their steeds--not cruelly but with a gentle touch to let the horses know a burst of speed was needed--and the race was quickly taken up. And while it is on I will beg a moment or so of the time of my new readers to make them acquainted with the heroes of this story. As related in the first book of this series, called "The Boy Ranchers; or Solving the Mystery at Diamond X," Nort and Dick Shannon, eastern cousins of Bud Merkel, went to the ranch of his father, Diamond X, to spend their vacation. While there certain mysterious happenings occurred. Dr. Hendryx Wright, a college scientist, with a party of helpers, was discovered digging not far from Diamond X. At first it was thought he was after a lost gold mine, but later it was disclosed that he was after the bones of a prehistoric monster for the college museum. The part that Del Pinzo, a rascally half-breed, played in this search and the activities of the boy ranchers, are fully set forth. Nort and Dick liked it so at Diamond X that they took up their home with Bud, and became partners with him, their father buying them a share in a ranch located in "Happy Valley," as the boys called it. Following the exciting times related in the first volume, the boy ranchers went to camp, they took the trail and also helped pursue a band of Yaqui Indians who escaped from their Mexican reservation, and the details of those activities will be found in the volumes specifically named for each line of activity. The book immediately preceding this is called "The Boy Ranchers Among the Indians; or, On the Trail of the Yaquis."