A narrow shelf existed around, the verge of a huge inland sea, or basin, rather.

Frank Reade, Jr. stopped and looked keenly about him.

Then a chill struck him.

An inkling of the truth came to him.

“Heavens!” he gasped. “I think I can understand it now!”

“Phwat, sor?”

“The berg has collapsed on the side we entered by, and we are imprisoned by the change!”

“Shure, sor, ye don’t mean it?”

“Yes, I do.”

Barney was astounded. Then a light broke upon him.