"Oh well—" He shrugged his shoulders and slipped into the straps of his pack. Then he went back again to the granite ledge. "I wonder if there's a way down," he said.
There was, but it took all of Jerry's strength to see him safely through. On a fan-shaped talus of spreading boulders he stopped. There was a limestone wall beyond. And at its base, from a crevice that was almost a cave, came a furious rush of air and steam.
It touched him lightly a hundred feet away, and he threw himself flat to escape the hot blast. Endlessly it came, with its soft, rushing roar, a ceaseless, scorching blast from the cold rocks.
"That's almighty funny," mused Foster, and sniffed the air. There was no odor.
"And is it hot!" he said. "Nothing like that in my geology book. And what is beyond? Looks like concrete work, as if someone had plastered up the cave." He picked his way quickly across the rock slope.
It was hard going. Below him the rocks and dirt went steep to the canyon floor. At its foot the blast swept diagonally over the slope. He must see what lay beyond....
"Curious," he thought; "curious if that is nature's work—and a lot more so if it isn't."
A rock rolled beneath his feet. Another! He scrambled and fought desperately for foothold in the slipping earth. Then, rolling and clawing, he rode helpless on the slide straight toward the mysterious blast. He felt it envelop him, hot and strangling. His lungs were dry and burning ... the blazing sun faded from the rocks ... the world was dark....