“Hear that?” he demanded.
Judy and Kathleen already had distinguished the distant sound of running water. The underground stream!
At the same instant that they heard the splash of water, Captain Hager’s flash beam focused upon the narrow opening in the cavern wall—the passageway for which he had searched.
“We near the end,” he said simply.
They moved quickly through the narrow corridor. The thunder of a distant waterfall they never were to see, was louder now in their ears.
The floor of the passageway sloped sharply downward. Kathleen slipped but did not fall, for Judy caught her arm to give her support.
Abruptly, the corridor turned, and the girls saw water ahead. The underground stream, quiet and dark, emerged from a wall of rock to flow tranquilly beneath the slightly arched cave-roof above.
Captain Hager halted. “We’ve come to the end,” he announced.
Judy and Kathleen were stunned. “The end,” Judy repeated, scarcely comprehending. “But I thought—”
“We can proceed no further without wading along the river bed,” the captain explained. “The water gradually deepens until it rises to the ceiling. At that point, one must dive through and swim underwater, or turn back.”