Little Snap failed to catch the rest, but he had heard enough to know that he must be active, too. From the sounds, he knew the party were leaving their underground rendezvous. Aware that it would not do for these men to capture his horse with the mail, his mind was filled with conflicting plans of action. His first impulse was to return the way he had come, but he realized that it would be impossible for him to cross the chasm, even could he scale the slippery ascent beyond. Possibly, if he were coming the opposite way, he might leap the abyss, though that would be extremely doubtful. Only one avenue of escape seemed open to him, and that was to follow upon the heels of his enemies! He had not a moment to lose if he did this, and, without further consideration, he glided across the cavern room in the direction taken by the five men. Guided by the sounds of their advance, while moving as noiselessly as possible himself, Little Snap threaded the circuitous passage, keeping but a few yards behind them. After a short distance, the way began to ascend by irregular stone steps, to climb which Little Snap had to exercise great caution not to betray his presence. Once, as the party suddenly paused, he found himself within a few feet of the group, but owing to the darkness he was not discovered. "Hang it!" exclaimed the chief, after a moment's stop, "I have dropped that letter somewhere. I think it must be where we were sitting. Blake, go back and find it; and then keep a watch over the entrance to the cave until we return." Little Snap held his breath at the sound of this order, and when he heard the man turning back, he felt that he was lost. Without losing his presence of mind, he shrank back as close to the nearest wall as he could, and silently awaited the approach of the other. He hadn't long to wait, for the next moment Blake's heavy step told that he was near at hand. Then the postboy felt his bulky form brush against him! "I shall be glad when we get out of this place!" muttered the man, as he stumbled on past the crouching figure of our hero. During this time the others were leaving the cavern, and as soon as he dared, Little Snap started forward, feeling now that every moment was of infinite value to him. A little farther on a streak of daylight struggling into the dismal pathway told that they were approaching the end of the passage. In fact, the men were already crawling out of the small aperture that afforded an exit from the cave. As closely as he dared, Little Snap followed after them, and when he could no longer hear their movements he ventured to peer out. As at the other place of entrance, the mouth of the cavern was overgrown with stunted bushes, so as to be well concealed from sight. He found, too, that the spot was nearly twenty-five feet from the ground, it being midway up the side of the bluff.