side of the Mound, and there came in the range of their
vision an Indian engaged in some mysterious occupation on the bank of
Buffalo Creek.

"He's at the Ice Box," declared Apple. "Now what do you suppose that
Indian's doing? Look at him dive."

"How can he stay under so long?" asked Glen, after they had watched two
or three minutes without seeing a head appear.

"I can't tell you. Maybe he swam under water and has come up in some
other place that we can't see."

But fully ten minutes later, while they still watched in great
curiosity, his head came into sight at about the place where he had
dived in, and a moment later they saw him draw his glistening body out
of the water.

"Where's he been?" said Apple. "He hasn't been under water all that
time."

"But neither did he come up anywhere that I could see," said Glen. "I
know what's happened," he added in an excited tone. "He's been in the
cave."

"I believe you," said Apple. "We guessed right. Ice Box and Deep Springs
mean the same place. I don't know about any Twin Elms but that cave is
there, at the Ice Box. I don't know why we never saw it, unless because
it's on the far bank and we always looked this side."

"Maybe its entrance is under water," suggested Glen. "That Indian dived,
you see, and we didn't see a sign of him again until he came back."

"That's the way of it, Glen. And that's the same Indian told us to look
for heap rock. I believe--" it was the romantic side of Apple now
appearing--"I believe he is the tribal guardian of the treasure and he
stays around here to guard it from our search."

"Maybe so," agreed Glen. "Anyway if the treasure's there we'll soon know
it. You think you can keep in your head the exact location where he
dived?"

"Yes. It's just at the bend of the Ice Box. Right opposite on the other
bank are those two old stumps--"

"Hold on," shouted Glen excitedly, seized with a great idea. "I'll bet
you those are the stumps of elm trees--the Twin Elms."

"You're right, Glen. I'm sure you're right. I can hardly wait to find
out."

"We don't want all the camp following us into this. When will be the
best time to hunt for it?"

"What's the matter with right now?" suggested Apple. "It's only a little
after five. Breakfast won't be called until eight. Father won't care
where we go so long as we get to camp in time for breakfast."

"But the Indian! What will he be doing while we explore his cave?"

"He won't be there. He hiked