“Do you see those lines?”
“Yes.”
“The highest one is fully two hundred feet.”
“That is true.”
“Well, have you never seen lines like those before?”
Frank studied the face of the cliff a moment.
Then he said:
“Yes, I think I have. They look like high water marks upon cliffs at the seashore.”
“Just so. Now, if they are water marks, it must mean that there have been times when this whole basin, this entire Polar country, has been under water.”
Frank was astounded.