Here he faced a notch in the cliff. At the apex he turned abruptly into a ragged vent that split the ponderous wall clear to the top, showing a narrow streak of blue sky.

At the base this vent was dark, cool, and smelled of dry, musty dust. It zigzagged so that he could not see ahead more than a few yards at a time. He noticed tracks of wildcats and rabbits in the dusty floor. At every turn he expected to come upon a huge cavern full of little square stone houses, each with a small aperture like a staring dark eye. The passage lightened and widened, and opened at the foot of a narrow, steep, ascending chute.

Venters had a moment's notice of the rock, which was of the same smoothness and hardness as the slope below, before his gaze went irresistibly upward to the precipitous walls of this wide ladder of granite. These were ruined walls of yellow sandstone, and so split and splintered, so overhanging with great sections of balancing rim, so impending with tremendous crumbling crags, that Venters caught his breath sharply, and, appalled, he instinctively recoiled as if a step upward might jar the ponderous cliffs from their foundation. Indeed, it seemed that these ruined cliffs were but awaiting a breath of wind to collapse and come tumbling down. Venters hesitated. It would be a foolhardy man who risked his life under the leaning, waiting avalanches of rock in that gigantic split. Yet how many years had they leaned there without falling! At the bottom of the incline was an immense heap of weathered sandstone all crumbling to dust, but there were no huge rocks as large as houses, such as rested so lightly and frightfully above, waiting patiently and inevitably to crash down. Slowly split from the parent rock by the weathering process, and carved and sculptured by ages of wind and rain, they waited their moment. Venters felt how foolish it was for him to fear these broken walls; to fear that, after they had endured for thousands of years, the moment of his passing should be the one for them to slip. Yet he feared it.

"What a place to hide!" muttered Venters. "I'll climb--I'll see where this thing goes. If only I can find water!"

With teeth tight shut he essayed the incline. And as he climbed he bent his eyes downward. This, however, after a little grew impossible; he had to look to obey his eager, curious mind. He raised his glance and saw light between row on row of shafts and pinnacles and crags that stood out from the main wall. Some leaned against the cliff, others against each other; many stood sheer and alone; all were crumbling, cracked, rotten. It was a place of yellow, ragged ruin. The passage narrowed as he went up; it became a slant, hard for him to stick on; it was smooth as marble. Finally he surmounted it, surprised to find the walls still several hundred feet high, and a narrow gorge leading down on the other side. This was a divide between two inclines, about twenty yards wide. At one side stood an enormous rock. Venters gave it a second glance, because it rested on a pedestal. It attracted closer attention. It was like a colossal pear of stone standing on its stem. Around the bottom were thousands of little nicks just distinguishable to the eye. They were marks of stone hatchets. The cliff-dwellers had chipped and chipped away at this boulder fill it rested its tremendous bulk upon a mere pin-point of its surface. Venters pondered. Why had the little stone-men hacked away at that big boulder? It bore no semblance to a statue or an idol or a godhead or a sphinx. Instinctively he put his hands on it and pushed; then his shoulder and heaved. The stone seemed to groan, to stir, to grate, and then to move. It tipped a little downward and hung balancing for a long instant, slowly returned, rocked slightly, groaned, and settled back to its former position.