"I move we go on down now," he suggested, walking to the edge of the huge crevice in which they were sitting. "It's only a couple of thousand feet." "Perhaps we might as well," agreed the Doctor, rising also. "When we get to the floor of the valley, we can find a good spot and turn in for the night." The incongruity of his last words with the scene around made the Doctor smile. Overhead the sky still showed a narrow ribbon of blue. Across the valley the sunlight sparkled on the yellowish crags of the rocky wall. In the shadow, on the side down which they were climbing, the rocks now shone distinctly phosphorescent, with a peculiar waviness of outline. "Not much like either night or day, is it?" added the Doctor. "We'll have to get used to that." They started off again, and in another two hours found themselves going down a gentle rocky slope and out upon the floor of the valley. "We're here at last," said the Big Business Man wearily. The Very Young Man looked up the great, jagged precipice down which they had come, to where, far above, its edge against the strip of blue marked the surface of the ring. "Some trip," he remarked. "I wouldn't want to tackle that every day." "Four o'clock," said the Doctor, "the light up there looks just the same. I wonder what's happened to George." Neither of his companions answered him. The Big Business Man lay stretched full length upon the ground near by, and the Very Young Man still stood looking up the precipice, lost in thought. "What a nice climb going back," he suddenly remarked. The Doctor laughed. "Don't let's worry about that, Jack. If you remember how Rogers described it, getting back is easier than getting in. But the main point now," he added seriously, "is for us to make sure of getting down to Arite as speedily as possible." The Very Young Man surveyed the barren waste around them in dismay. The floor of the valley was strewn with even larger rocks and bowlders than those on the surface above, and looked utterly pathless and desolate. "What do we do first?" he asked dubiously. "First," said the Doctor, smiling at the Big Business Man, who lay upon his back staring up into the sky and paying no attention to them whatever, "I think first we had better settle ourselves for a good long rest here." "If we stop at all, let's sleep a while," said the Very Young Man. "A little rest only gets you stiff. It's a pretty exposed place out here though, isn't it, to sleep?" he added, thinking of the sparrow and the lizard. "One of us will stay awake and watch," answered the Doctor. CHAPTER XVI THE PIT OF DARKNESS At the suggestion of the Very Young Man they located without much difficulty a sort of cave amid the rocks, which offered shelter for their rest. Taking turns watching, they passed eight hours in fair comfort, and by noon next day, after another frugal meal they felt thoroughly refreshed and eager to continue the journey.