The marshal, already familiar with the mystery, and baffled by it, searched again perfunctorily. Uncle Dick hunted hither and yon with feverish activity, at first confidently, then doubtfully, finally in despair. He, in his turn, could find no further clue. He gave over his efforts eventually, and stood silent beside the marshal, staring bewilderedly. About the amphitheatre formed by the pool, pines grew in a half-circle, save where the narrow channel of the stream descended. But between the barricade of the trees and the basin of water lay the smooth stretch of sand, slightly moist from out-flung spray of the falls. Upon that level surface, the tracks showed forth--undeniable, inexplicable. They marched without deviation straight to the base of the great cliff. There, within a little space, they grew confused, as from much trampling. But they did not return; they did not go elsewhere. There was a clear distance of a rod over the sand to the rocky ground where the trees grew. On the other side lay the deeps of the pool. Before them reared the impassible wall of the precipice. And there the tracks ended.
Uncle Dick knew the place well, and on that account the mystery was the greater. He could find no possible explanation, however wildly improbable, of that disappearance. The broad sheet of the falls fell close to the cliff's face. The rock was unworn by the torrent, without recess or cavern. And that precipice, twice the pool's width, mounted sheer a hundred feet, the height of the cascade. The front was unbroken save by tiny rifts and narrow ledges, where dwarfed ground pines clung precariously. With a muttered curse, the old man turned from his vain contemplation of the cliff, and let his troubled eyes rest on the pool. Suddenly, he started. He remained motionless for a moment, then, with nervous haste threw off his shirt, and trousers. Marshal Stone, chancing to look that way, was astonished to see his companion naked, poised at the water's edge. He had time to note with admiration the splendid figure, still supple and strongly muscled despite the four-score years. Then Uncle Dick leaped, and dived. It was long seconds before he reappeared, only to dive again. He paid no attention to the marshal's remonstrances. Only when he was convinced of the uselessness of further search in the pool's depths, did he give over the task, and cast himself down on the sand to rest, panting and trembling a little from fatigue.
"They hain't thar," he said, with grim conviction. Then he voiced the question that hammered in his brain: "Whar be they?"