That caused Roger to awaken to the fact that he was not paying as much attention to his progress through the populous town as he should; and, having had his fears aroused, he now began to keep a close watch for signs of trouble ahead. Being thus fully on their guard they were able to reach the border of the prairie dog settlement without having met with any disaster; and, the last they saw of it, several of the boldest of the natives had crept out of their burrows, and seemed to be "barking them a farewell," as Roger laughingly said. While they were jealous concerning their ammunition, hoarding it against a possible emergency, they seldom lost an opportunity to wet a line in the great river, whenever their camp was close by the bank. Roger always carried hooks and lines along with him, so that on the present occasion he was well equipped to capture all the finny prizes they needed for food. Many a night, while Dick slept, the other would sit on the river bank, with his line in his hand, waiting for a bite, and seldom did his vigilance go unrewarded, so that they had fish for breakfast on numerous occasions. It happened that once again they discovered a place where undoubtedly the expedition they were following must have waited over night. There were the plain tracks of horses' hoofs, and also the ashes of several fires, for, being in such numbers, the explorers of the Missouri did not feel compelled to hide whenever they made camp, in order to keep their location a secret from spying eyes. Of course Roger asked his companion to try to find out from various signs, which could be readily picked up, whether they were now any closer to the column than on that other occasion, when they rested in the abandoned camp of the explorers. This Dick did in a most thorough fashion, and, after concluding his labors, he announced it as his belief that they had indeed gained another day. "Is that all?" remarked Roger, evidently disappointed; and from his manner one might believe he had expected to hear Dick say they would overtake Captain Lewis by another day or so. "On my part," declared Dick, "I think that we are doing as well as we ought to expect. All I ask is that things go right along as they have been doing. We are seeing some wonderful sights while we keep on the move each day. And, besides, you forget, Roger, that the sooner we come up with the expedition, the sooner we must be taking the back trail. Now that we're away out here in this strange country I'd like to see all I can of it."