"Where do we go from here?" inquired Joe.
"Anywhere but into caves," his brother replied. "I think we might as well follow along the shore again. One thing is certain—there have been people on this island, and not long ago at that. Why—"
Suddenly he stopped.
"Listen."
They remained quiet. Frank had heard what seemed to him like a distant shout, and as they listened he heard it again. It was a faint call that echoed among the rocks far ahead of them.
The boys looked at one another. Frank pressed his fingers against his lips as a caution to remain silent. Then, from among the rocks above them they heard another shout, clearer this time, evidently in response to the one they had first heard. The first shout was again repeated; then silence fell.
"That proves it," said Frank quietly. "There are people on this island."
"They're calling to each other."
"Sounded like that."
"We'll head down in the direction of the place that first shout came from. It was some one calling to some one else back up here among the rocks."
They went on in the direction from which the first call had been heard. For over ten minutes they proceeded carefully among the
