They had traveled over the savanna for perhaps an hour when Sierra turned to the left, entering the forest that covered the flanks of a great mountain. The trees closed on them. Graydon could see no trail, yet she went on without pause. Another hour went by and the way began to climb, the shade to deepen. Deeper it became and deeper, until the girl was but a flitting shadow.
Once or twice Graydon had glanced at the three men behind him. The darkness was making them more and more uneasy. They walked close together, eyes and ears strained to catch the first faint stirrings of ambush. And now, as the green gloom grew denser still, Soames ordered him to join Dan and Starrett. He hesitated, read murder in the New Englander's eyes, realized the futility of resistance and dropped back. Soames pressed forward until he was close behind the scowled figure. Dan drew Graydon between himself and Starrett, grinning.
"Soames has changed his plan," he whispered. "If there is trouble, he shoot the old devil— quick. He keep the girl to make trade wit' her people. He keep you to make trade wit' the girl. How you like—eh?" Graydon did not answer. When the Frenchman had pressed close to him, he had felt an automatic in his side pocket. If an attack did come, he could leap upon Dan, snatch the pistol and gain for himself a fighting chance. He would shoot Soames down as remorselessly as he knew Soames would shoot him.
Darker grew the woods until the figures in front were only a moving blur. Then the gloom began to lighten. They had been passing through some ravine, some gorge whose unseen walls had been pressing in upon them, and had now begun to retreat.
A few minutes longer, and ahead of them loomed a prodigious doorway, a cleft whose sides reached up for thousands of feet. Beyond was a flood of sunshine. Sierra stopped at the rocky threshold with a gesture of warning, peered through, and beckoned them on. Blinking, Graydon walked through the portal. He looked out over a grass-covered plain strewn with huge, isolated rocks rising from the green like manghirs of the Druids. There were no trees. The plain was dish-shaped; an enormous oval as symmetrical as though it had been molded by the thumb of some Cyclopean potter. Straight across it, three miles or more away, the forests began again. They clothed the base of another gigantic mountain whose walls arose, perpendicularly, a mile at least in air. The smooth scarps described an arc of a tremendous circle—round as Fujiyama's sacred cone, but many times its girth.
They were on a wide ledge that bordered this vast bowl. This shelf was a full hundred feet higher than the bottom of the valley whose side sloped up to it like the side of a saucer. And, again carrying out that suggestion of a huge dish, the ledge jutted out like a rim. Graydon guessed that there was a concavity under his feet, and that if one should fall over the side it would be well-nigh impossible to climb back because of the overhang. The surface was about twelve feet wide, and more like a road carefully leveled by human hands than work of nature. On one side was the curving bowl of the valley with its weird monoliths and the circular scarp of the mysterious mountains; on the other the wooded cliffs, unscalable.
They set forth along the rim like way. Noon came, and in another ravine that opened upon the strange road they had snatched from saddle bags a hasty lunch. They did not waste time in unpacking the burros.