In an instant all was intense excitement on board the motor boat. There was only one way in which the savages could reach them, and that was to block their passage out and starve them to death! Had this system been resorted to? Had the cunning savages obstructed the little stream while the lads were busy building their fire and observing their menagerie, as they called it?
These questions were in the minds of all as efforts to back the Black Bear were redoubled. Finally Jack opened a panel at the rear and looked out, a thing he should have done at first.
What he saw was a large log blocking the channel. The propellers were pounding against it, and one of them was broken.
"I guess the little brown men have got us good and plenty," he said, slowly, as he reached forward and shut off the power. "While we were playing about the blaze they plugged the river."
"They can't get in here, anyway!" Frank consoled.
"No; they'll wait for us to get good and hungry and go out!" Jack replied.
The situation was a serious one. The head hunters now appeared in the open space about the blazing tree and shook their spears and their clubs at the boat. Now and then an arrow with a poisoned tip struck the side of the Black Bear.
"They'll never leave until they get us!" Jack said, presently, "and so we may as well get a few of them. Get your guns, boys."
"Just you wait, old hard luck prophet," Frank exclaimed. "Look up through the glass panel above your head and tell me what you see."
"Well," Jack replied, "it looks like we had established communication with the Nelson at last. And also with the Greatest Show on Earth!" he added, as a mighty roar went up from the shore.