“Whatever it is, I can swear that it is of importance to us,” said I. “I could read that on his face as he gave it.”

“Unless we have come upon a primitive practical joker,” Summerlee suggested, “which I should think would be one of the most elementary developments of man.”

“It is clearly some sort of script,” said Challenger.

“Looks like a guinea puzzle competition,” remarked Lord John, craning his neck to have a look at it. Then suddenly he stretched out his hand and seized the puzzle.

“By George!” he cried, “I believe I’ve got it. The boy guessed right the very first time. See here! How many marks are on that paper? Eighteen. Well, if you come to think of it there are eighteen cave openings on the hillside above us.”

“He pointed up to the caves when he gave it to me,” said I.