They started for the spot; but before they had taken half a dozen steps once more the thunderous sound was heard; and under them the mountain quivered. As the boys were not more than human, it was only natural that they should halt until the convulsion had passed. Bob could not help clutching a spur of rock as though he feared that something dreadful was about to happen.
As the roaring noise began to die out the boys caught the cries of Spanish Joe once again. He seemed to be nearly frantic with fear, and was calling upon his cowboy crony not to forsake him in his extremity.
"It's going to tumble on me the next shake! Hurry, Nick, or I'm a goner!" they heard him pleading.
"Whatever can have happened to him?" asked Bob, awed by the exciting incidents by which they seemed to be surrounded.
"I reckon he's caught in some sort of trap, judging from his talk," Frank sent back over his shoulder; for both of them were climbing upward as rapidly as the conditions allowed.
It was no wonderful feat for Frank to make straight for the spot where the loud voice came from. He had located it; and even when Joe ceased calling for a minute or two, Frank was able to continue right on.
Apparently the cowman had heard some sound that told him of their coming. That accounted for his silence, since he was listening eagerly. And of course he fully expected that it must be Nick Jennings hastening to his assistance, perhaps with Peg at his heels. At least his words would indicate as much, when he cried again.
"Hurry, boys! There ain't any too much time. This way, right straight ahead! Oh! I'm in a hole, I tell ye. Ye ain't stopping, are ye? Come on! come on!"
They were now close to where the speaker must be located. Frank was already straining his eyes to make out his figure, so as to get some idea as to the nature of the new task that confronted them.
He presently could make out some object that squirmed and tugged between groans.