After this day and night, crowded so full of incident, four days of steady travel brought General Lyle's expedition to a point close to the boundary-line between Kansas and Colorado, where their surveys were to begin. The last hundred miles of their journey had been through a region studded with curious masses of sandstone. These were scattered far and wide over the Plains, and rose to a height of from one hundred to three hundred feet, resembling towers, monuments, castles, and ruins of every description. It was hard to believe that many of them were not the work of human hands; and to Glen and Binney they formed an inexhaustible subject for wonder and speculation.