When the northern host swept southward, and overwhelmed Jerusalem, the onrushing wave was fretted with fire; later, when the wave of war retreated, it carried back the detritus of a ruined civilization.

These cloud mountains vanished in the azure as quickly as they were developed, leaving no detritus; but they were not a whit less real or interesting on this account.

It is a mass of volcanic matter to which the air, the rain, and the passage of a million years have given an all-covering verdure except upon the loftiest peaks, have cut into strangely shaped cliffs, sloping hills, spacious vales, and shadowy glens and dingles, and have poured down the rich detritus and humus to cover the coral beaches and afford sustenance for man and beast.

The glacial erosion of most of the Shasta lavas produces detritus, composed of rough, sub-angular boulders of moderate size and of porous gravel and sand, which yields freely to the transporting power of running water.

The bottom of the storm is broken up into innumerable waves and currents that surge against the hillsides like sea-waves against a shore, and these, reacting on the nether surface of the storm, erode immense cavernous hollows and cañons, and sweep forward the resulting detritus in long trains, like the moraines of glaciers.