The two galloped away straight toward the West, and, as the forest offered no difficulties, they were not compelled to check their speed. But in less than an hour Breakstone, who was in advance, pulled his horse back sharply, and Phil did the same. "Look, Phil!" exclaimed Breakstone, making a wide sweep with his hands, while face and eyes were glowing, "See, it is Texas!" Phil looked. None could have been more eager than he was. The hill seemed to drop down before them sheer, like a cliff, but beyond lay a great gray-green waving sea, an expanse of earth that passed under the horizon, and that seemed to have no limit. It was treeless, and the young grass had touched the gray of winter with fresh green. "The great plains!" exclaimed Phil. He felt an intense thrill. He had at last reached the edge of this vast region of mystery, and to-morrow they would enter it. "Yes, the great plains," said Bill Breakstone. "And down here, I think, is where our wagons will have to pass." He turned to the left and followed a gentle slope that led to the edge of the plains. Thus, by an easy descent, they left the forest, but when they turned back Phil’s eye was caught by a glittering object: "Look, Bill!" he exclaimed. "See the arrow! What does it mean?" An arrow with a deeply feathered shaft had been planted deep in an oak tree. Evidently it had been fired from a bow by some one standing on the plain, and it was equally evident that a powerful hand had drawn the string. It stood out straight and stark as if it would stay there forever. Bill Breakstone rode up to it and examined it critically. "It’s a Comanche arrow, Phil," he said, "and, between you and me, I think it means something: "An arrow I see Stuck in a tree, But what it does mean Has not yet been seen-- "Especially when it’s coupled with the fact that you saw Black Panther’s face in the thicket. I may have an imaginative mind, Sir Philip of the Forest, soon to be Sir Philip of the Plain, but this arrow I take to be our first warning. It tells us to turn back, and it may have been fired by Black Panther himself, late Knight of the Levee and of Strong Drink." "Will we turn back?" asked Phil somewhat anxiously. Bill Breakstone laughed scornfully. "Do you think a crowd like ours would turn back for a sign?" he asked. "Why, Phil, that arrow, if it is meant as a threat, is the very thing to draw them on. It would make them anxious to go ahead and meet those who say they must stop. If they were not that kind of men, they wouldn’t be here." "I suppose so," said Phil. "I, for one, would not want to turn back." He rode up to the tree, took the arrow by the shaft, and pulled with all his might. He was a strong youth, but he could not loosen it. Unless broken off, it was to stay there, a sign that a Comanche warning had been given.