"Not a bit of it. It's as full of mountainous regions and flat, depressed plains and valleys as the Rockies themselves."
"Gee whiz! I'd hate to hit one of them. I——"
Merritt stopped short. A terrific crash shook the submarine from stem to stern. Rob saved himself from falling into the machinery by seizing a rail.
For an instant the vibration lasted, and then the diving craft came to a dead stop.
The boys gazed at each other with blanched faces.
Did the crash mean that they had actually struck one of the submerged ranges that make deep sea traveling full of dangers? Had Mr. Barr delayed too long in rising?
On the answer to these questions both boys felt that their lives depended.
They were still regarding each other with consternation when the ensign burst into the cabin.
"Shut off the engines instantly!" he ordered.
"What have we struck? That submerged cliff that you feared?" Rob managed to gasp out, while Merritt hastened to obey the officer's command.