The next instant fragments of rock scattered about his head and he heard a sharp report somewhere outside.
Like a flash, the boy threw himself flat on his stomach and wriggled back into the tunnel.
"They're firing at us!" cried Tubby.
"Yes, but who?" demanded Merritt.
"That's the question," was Rob's rejoinder. "I guess it must be Indians, but then, again, it may be hunters, who, having seen something move, fired. I'm going to try to find out."
"Oh, Rob, be careful," begged Merritt.
"That's all right. Here, Bill, lend me that long pole you've got."
Bill Simmons obediently handed over a long branch he had broken off to use as a guiding staff, before they entered the dark passageway. Rob pulled off his sombrero and stuck it on the pole.
Then he cautiously poked it out of the rocky portal.
"Bang!"