The ridge above sheltered the spot from the hot sun, and there was a cavity in the cliff which promised a secure resting place.

As he stepped out on the shelf Nestor paused and pointed to a collection of three rocks lying in plain view.
"What is it ?" asked Jimmie, his eyes on the sandwich packet.
"Read it," replied Nestor.
"Head to the south!" shouted Shaw.

"Who put that here ?" Nestor looked keenly into the astonished face before him.
"No tricks, now," he said.

"Which of you boys placed this stone signal ?" No one made answer, and Frank bent down to make a closer inspection of the rocky floor of the shelf.

Presently he gave a wild whoop and arose to his feet with something in his hand.
"What do you know about this ?" he demanded.