Neither girl offered to stir from under the tree where they had halted in order to go on with their pilgrimage. The mystery of the noise that they had just heard made their adventure seem far more perilous. What on earth was it? What did it mean? The atmosphere was clear. The travelers guessed they must have come to about the center of the island. It was a broad, open plateau, covered with grasses and wild flowers. Neither of the girls thought of how curious it was to find the grass cropped as close to its roots as though it had been cut down by a mowing machine. Phil was walking slowly ahead. There was an opening through a double avenue of trees, and Phil wanted to find out whether they could get through the woods by this cut. For the moment Madge's back was turned to Phil. She was reaching up for a particularly splendid bunch of Virginia creeper that clung to a branch over her head. Like a roll of thunder from a clear sky, or the rumble of heavy artillery, came the noise that they had heard before. It was indeed the rushing of many feet and it was coming nearer. Phil ran toward a low-branched tree. "Climb the tree, Madge!" she cried. But Madge only stared intently ahead of her. Some distance ahead a single dark object made its appearance. It walked on four feet, had a thick, shaggy mane, and its long black tail swept the ground in a proud arch. Its coat was rough---- Madge clapped her hands. To Phil's horror her chum started to run forward, instead of taking refuge in a tree. "It's only a strange-looking horse!" she cried in relief. Madge had never in her life seen a horse of which she felt afraid. At almost the same instant, back of the single horse, which was plainly the leader of a drove, appeared another, then a dozen, twenty or thirty more horses. The entire drove was galloping recklessly ahead. It was the noise of their charge that had indeed sounded like a rush of cavalry. The leader of the horses caught sight of Madge. What must it have thought? A human being had appeared out of nowhere in the midst of its haunts. The wild horse stopped short for an instant, then gave a long neigh to its companions. The other horses ceased their charge; they, too, sniffed the air with the same attitude of surprise and hesitation. Some of them pawed the ground in front of them. Phil, from her position in the tree, could see everything that happened. She thought she was experiencing a nightmare, or else that she had beheld an apparition which had come out of the pages of her ancient mythology. To Phil's amazement, Madge stood still during the brief instant when the horses hesitated. It was then she might have saved herself, but she lingered for an instant, then turned to run.