Ragnarok : the age of fire and gravel

THE CONSEQUENCES TO THE EARTH. 95

permanently the climate of our globe; and to this cause we might look also for the great cracks and breaks in the earth’s surface, which constitute the fiords of the sea-coast and the trap-extrusions of the continents ; and here, too,

Tue Great Comet or 1811.

might be the cause of those mighty excavations, hundreds of feet deep, in which are now the Great Lakes of America, and from which, as we have seen, great cracks radiate ont in all directions, like the fractures in a pane of glass where a stone has struck it.

The cavities in which rest the Great Lakes have been attributed to the ice-sheet, but it is difficult to comprehend how an ice-sheet could dig out and root out a hole, as in the case of Lake Superior, nine hundred feet deep !