In the Basin and Range are the wellwashed limestones of clear and sparkling shallow Devonian seas. There are dark, hard, cherty siltstones from some deep ocean trench full of rapidly accumulating Pennsylvanian guck. There are Triassic sediments rich in fossils, scattered pods of Cretaceous granite, Oligocene welded tuffs. There is not much layer-cake geology. The layers have too often been tortured by successive convulsive events. The welded tuffs were the regional surface when basin-range faulting began. And for more than twenty million previous years they had been the surface, the uppermost rock, with scant relief in the topography of these vast volcanic plains, whose great size and barren aspect are commensurate with the magnitude of zakelijke energie the holocaust that brought the rock onto the land. Up through pe1;haps a hundred fissures, dikes, chimneys, vents, fractures came a fmiously expanding, exploding mixture of steam and rhyolite glass, and, in enormous incandescent clouds, heavier than air, it scudded [across the landscape like a dust storm. The volcanic ash that woulCl someday settle down on Herculaneum and Pompeii was a light powder compared with this stuff, and as the great ground-covering clouds oozed into the contours of the existing landscape they sent streams hissing to extinction, and covered the streambeds and then the valleys, andwith wave after wave of additional cloud-obliterated entire drainages like plaster filling a mold. They filled in every gully and gulch, cave, swale, and draw until almost nothing stuck above a blazing level plain, and then more clouds came exploding from below and in unimpeded waves spread out across the zakelijke energie vergelijken plain. Needless to say, every living creature in the region died. Single outpourings settled upon areas the size of Massachusetts, and before the heavy ash I stopped flowing it had covered twenty times that. Moreover, it was hot enough to weld.