They started forward once more, and were going along at a pretty good clip, the road having improved in spots.
“I wonder when we’ll get to that underground city?” said Ned, for perhaps the tenth time that day.
He had no sooner spoken than the earth trembled under the auto. The machine seemed to stand still. Then, with a sickening motion it plunged forward and downward.
A big hole had opened in the road and let the car and its occupants through the surface of the earth. The machine slid forward, revealing, near the top of a shaft, a brief glimpse of several ruined buildings.
“It is the underground city!” exclaimed the professor.
Then there came intense darkness.
[CHAPTER XIX.]
IN AN ANCIENT TEMPLE.
The auto seemed to be bumping along downhill, for at the first evidence of danger Jerry had shut off the power and applied the brake. But the descent was too steep to have the bands hold.