“Why, how serious you are! You worry me, Doctor. Won’t you--” “Not now,” he interrupted hastily. “I shall be obliged to explain soon enough--after I have made my decision. To-morrow I’ll tell you--well, tell you all that I dare tell.” He came to a halt as he finished speaking. They were following a well-defined trail that led them among natural obelisks of stone, tall and freakish. There was no other route to the floor proper of the valley. And at their very feet yawned a hole of large dimensions. Shonto sank to his knees and looked in. “I thought as much,” he muttered. “Look, Charmian! See those skeletons down in there?” She knelt beside him, and when her eyes became accustomed to the gloom of the hole she saw the skeletons and skulls of many animals. The walls of the hole were of solid rock, though masonry was not in evidence. The floor was level and many times wider than the mouth. This made the whole assume the shape of a funnel upside-down or an Indian wigwam. “Why, they couldn’t get out!” cried Charmian. “It is impossible to climb those walls.” “And you’ll notice that the hole is directly in the middle of the narrow pass from the cliffs above,” said he. “This, Charmian, is an Indian man-trap. In years gone by it was made here by residents of the valley to trap any enemies that might come down the trail to attack them. The hole was covered with light boughs, perhaps, with earth spread on top to hide them. I know this to be a trick of the Klamath Indians and the Pitt River tribes. But we are hundreds of miles from their stamping ground. We are in the rocks, you’ll notice. There is not a grain of dirt near us. This accounts for the hole’s not filling up with debris and disappearing through all these years. It’s been gouged with infinite pains in comparatively solid stone. It’s conclusive now that at one time the Valley of Arcana was inhabited and was the scene of tribal warfare. That was doubtless years before the fire swept down the forest and the chaparral locked the valley against intrusion.” “Oh, isn’t it all interesting?” she cried, dark eyes aglow. But the enthusiasm died out of them as she took note of the continued gravity of her companion’s mien. “Oh, you worry me so!” she complained again. “Please don’t look so solemn. Tell me, and let me help.” “You can’t,” he told her, forcing one of those rare smiles that almost beautified his face. “I alone can work out an answer to the problem. And I will know the answer by to-morrow morning. Meantime I’ll try my best to forget it.” A little farther on they found another man-trap, similar to the first. Then they left the cemeterial region of obelisks and passed out upon the broad floor of the cañon.