That would be a channel, wouldn't it? And it might be a lost channel at that! Why didn't I think of that before."

The boy was so full of the thought, so enthusiastic over the thing it might mean, that he concluded to make a quiet investigation on his own hook, saying nothing to the others regarding the matter.

"What was it you said about some underground stream?" asked Captain Joe. "You started in to say something about it and then stopped abruptly."

"Oh, it just occurred to me that there might be an underground river somewhere around here, but I guess that's just a dream. There couldn't be any river, you see, for the ground is rocky, and there seems to be no place for an underground stream to get its supply."

"No," the old captain agreed, "there can't be any underground stream that's a sure thing. If there are caverns they are dry."

Clay chuckled to himself, and went into the cabin after Alex.

"Come on, Redhead!" he cried catching the boy by the arm. "We are now going ash.o.r.e to dig up the lost channel."

"That's a nice pleasant little job, too!" Alex declared.

"Well, come on," Clay insisted. "We'll go over and make a start, anyway. We may be able to find out if the outlaws are really here."

Explaining to Captain Joe and the others that they were going only a short distance from the sh.o.r.e, the boys launched the canoe and were soon on the sloping sh.o.r.e of the peninsula. Once across they hid their canoe in a thicket which overhung the stream and disappeared in the interior.

"Now, look here," Clay said as he stopped and sat deliberately down in the shade of a great tree, "I've got an idea."

Alex stared hard in pretended wonder and amazement.

"Where did you get it?" he asked.

"Brain cell opened and gave it to me," Clay answered.

"Well, come across with it," Alex urged.

"Captain Joe wants to know where the water comes from to make the west river so large at its mouth," Clay went on. "I started in to tell him that there might be a subterranean stream somewhere hereabouts, but I thought he would laugh at me and so kept my mouth shut."

Alex sprang to his feet and swung round and round on his heels, chuckling and shaking hands with himself.

"That's the idea!" he cried. "That's just the idea! There is a subterranean stream here somewhere! Look at the way the rocks are piled up, and look at the long slope from the top of the ridges to the level of the river. There are catch basins here somewhere, and water pouring into the river that no one knows anything about."

"Now go a little farther," Clay suggested. "Figure that at some time, say two or three hundred years ago, this subterranean channel lay open to the sun. Now what do you make of it?"

"Holy smoke!" almost shouted Alex. "I make a lost channel!"

"There you are!" Clay began, "and all we've got to do is to just look around and find it. We've got plenty of time."

"That will be some cheerful job, too," Alex commented. "We've only got about forty thousand square miles of territory to look over."

"I think," Clay said, "that we have the idea, and that is the main thing. The rest is only a matter of detail."

As the boys sat under the tree, Alex having dropped down to the turf again, a rustling of bushes was heard to the east and they turned in that direction, scanning the thicket closely. Then Alex seized Clay by the arm and pointed away through the underbrush.

"Did you ever see that figure before?" he asked.

"Looks to me to be about the size of Max," Clay answered. "I wonder if he is watching us, or whether he is only looking in the direction of the _Rambler_. Anyway, we'd better move."

The boys shifted their position some yards to the north and crouched down again. The bushes showed motion once more, and they saw the figure they had observed moving toward the bank of the west river.

"He never saw us!" cried Alex. "He is sneaking down on the _Rambler_."

"Yes," Clay replied, "and there are two or three just behind him."

"I had an idea," Alex chuckled, "that things would begin to liven up as soon as we got into this country. This will please Captain Joe!"

"Captain Joe," Clay replied, "seems inclined to take things rather seriously. The chances are that he is wondering now, night and day, how four rattleheaded boys ever got so far over the world without being murdered or sent to the penitentiary. Still, he isn't always pa.s.sing out advice."

From their new shelter, the boys now saw Max and three men pa.s.s to the west and stand under a screen of boughs looking down toward the _Rambler_.

"The war is on, I guess," Clay said. "Those fellows were here waiting for us to come back. Did it ever occur to you that they know about our having that mysterious map?"

"Now you've said something," Alex exclaimed. "That map was intended for those opposing the Fontenelles. It was given to us by mistake, and the people who should have had it know that we've got it. That's why they're watching us so. Wonder we never thought of that before."

"It seems to me that you've struck it right," Clay answered. "They've been waiting here all this time for us to come back it seems."

"Then I should think they'd keep out of sight until we get busy looking for the channel. They surely won't want to drive us away before we demonstrate what we know about it."

"I presume they think they are keeping out of sight," Clay decided.

"Well, they're not keeping very close watch, for they don't seem to know that we're on sh.o.r.e."

"Don't be too sure of that," Clay answered. "They may be watching us this minute. Perhaps we'd better move."

As the boys spoke, Max and his three companions started at a swift pace up the bank of the stream keeping always out of view of the boat.

They pa.s.sed the place where the boys lay in hiding and for a moment the lads heard them pushing through the underbrush.

"They've probably gone to their tent now," Alex suggested, "and I'm going to follow on and see if I can locate them."

"All right," Clay said, "only be careful. I'll go back to the boat and tell the boys what's going on. Be sure you don't get captured, now,"

he added as Alex turned to the thicket to the north.

"No danger of that," the boy grinned and the next moment he was out of sight, pushing through the thicket in the direction taken by Max.

Clay stood for an instant longer where the boy had left him and then moved in the direction of the river.

But his progress toward the stream came to an abrupt termination in a minute. He tripped over what he at first believed to be a running vine and fell to the ground. Then, as he lifted himself to a sitting position, he saw the obstacle over which he had fallen was a rope and that it was held in the hands of two evil looking men.

The men, bearded and dirty, broke into a laugh over Clay's look of amazement. They sprang toward him and in a moment he was relieved of his weapons. The boy sat perfectly still, for the attack had come so suddenly that he could hardly comprehend the situation.

"Ain't it the cute little child?" guffawed one of the men, slapping his knees and bending down to look the boy in the face.

"He's all of that," replied the other. "This is the little boy that's come out here to find a hidden channel that no one else can find. He used to be a real cute little newsboy in Chicago, and directly he'll wish he was back selling newspapers on Clark street!

"Are these all the poppers you have, kid?" he asked pointing to the revolvers which had been taken from the boy. "You might injure yourself by carrying them."