As fast as the eye could follow, sheets of flame shot out of the sea of smoke, climbing higher and higher, in lightning flashes, until the lurid tongues licked the air a quarter of a mile above the startled wilderness.

Explosion followed explosion, some of them coming in hollow, reverberating booms, others sounding as if in mid-air.

The heavens were filled with hurtling rocks; solid masses of granite ten feet square were thrown a hundred feet away; rocks weighing a ton were hurled still farther, as if they were no more than stones flung by the hand of a giant; chunks that would have crashed from the roof to the basement of a sky-scraper dropped a third and nearly a half a mile away.

For three minutes the frightful convulsions continued.

Then the lurid lights died out of the pall of smoke, and the pall itself began to settle.