“Our earth, like the other planets, was one of the knots of denser matter on the two-armed luminous spiral which began circling the sun. There were smaller particles which were attracted to the earth by earth gravity and which increased the size of the earth till it was far larger than it is now. Ever since, the earth has been shrinking periodically, and when it shrinks, its surface becomes wrinkled, and these wrinkles we call mountain ranges.”
“Of course,” interpolated Ace, shining eyed, “the crust of the earth got cooled, while the inside was still a mass of molten metal and gas, which kept boiling over on to the crust,—couldn’t you say, Mr. Norris?”
“You’ve got the idea.”
“I s’pose that’s the hot place!” chuckled the old man.
“Probably where they got the idea. In time the metals and heavier substances sank, while the lighter ones rose as granite rocks, till there was an outer shell miles thick.
“The Valley of Ten Thousand Smokes, in Alaska, is a volcanic region where the ground is hot and breaks through with one even now,—I was there several years ago,—but generally speaking, this earth has a crust 150 miles thick.
“As I was saying, the continents are built of the lighter granite, chiefly, while the oceans lie on the heavier basalt.”
“But I thought you said we were on a chunk of basalt now,” said Ted.
“We are. You know the Pacific has flowed where now you see these peaks, as the high lands have been worn down between successive upbuildings.”
“But—where did the water in the ocean come from in the first place?” marveled the old prospector.