His companions hastened to his side. There they saw that, extending all the way across the floor of the cave, was a great crack, the other side of which they could not discern. Silently Andy picked up a stone and dropped it down. It was many seconds before, from the black depths, came floating up the echoes of the crash as the rock found bottom.
"By Jove!" whispered Frank. "That must go all the way down to the foot of the hill—thousands of feet!"
"And if you had fallen—" began his brother.
"But he didn't," said Billy quickly, for he was in the habit of looking on the bright side. "Well, this ends the cave as far as we are concerned. We can't go any further, and all we can do is to go back to where we first found the gold and get out as much as we can."
"That's right," agreed the Racer boys, and, after another glance into the black depths before them, they turned back. A look from the mouth of the cave showed them that the terrific storm was still keeping up.
CHAPTER XXVIII
THE RISING WATER
"Well, how much do you think we've got?" asked Andy Racer, as he sat down on a pile of dirt, and looked at a mass of dull, gleaming yellow near the side of the cavern.
"Oh, we must have two or three thousand dollars' worth," declared Frank.
"More than that," came from Billy, who was wielding a shovel, pausing at intervals for a rest. "Of course this isn't pure gold, as it's mixed with clay and earth, to say nothing of the rocks, but with all that we must have nearly five thousand dollars' worth."