Nature removes mountains, or creates them, at pleasure. She also makes and unmakes lakes and rivers, to say nothing of oceans and continents. In California, and doubtless in other parts of the world, there are as many dead as living rivers. The miners of California have already discovered the old channels of a dozen or more dead rivers, as they call them, encased and sealed up in the very heart of the mountain ranges, and extending in some instances hundreds of miles in the general direction of the ranges, and leaping from mountain to mountain at a common level or grade. These ancient channels are filled with sand, gravel, and small bowlders, evidently worn and polished by long attrition. Some of the channels are a mile wide, or more, and from ten to one hundred feet deep. In the angles or eddies, the sands are found to be exceedingly rich in gold, sometimes yielding fifty dollars or more to the cubic yard. It is estimated that over five hundred millions of dollars have already been taken from the sands of these dead rivers, and that they are now yielding at least ten millions a year. It is evident that these dead rivers must have been living rivers long before the volcanic era arrived, which elevated the ancient valleys into mountain ranges, and depressed the ancient mountain ranges into valleys. In the South-American earthquake of August, 1868, thirty thousand lives were lost, several cities entirely obliterated, and three hundred millions of dollars' worth of property destroyed. A tidal wave, more than forty feet deep, swept over the land and deposited, high and dry, and beyond recovery, several first-class ships; the effect of this earthquake was felt along the coast for a distance of six to seven thousand miles. In October of the same year, the city of San Francisco was visited by an earthquake, which shattered many buildings, and destroyed several lives. It is supposed that this was but a prolongation of the South-American earthquake. In some parts of California and South America, thunder and lightning seldom occur, while earthquakes are frequent; in regions like these, earthquakes would seem to be a substitute for thunder and lightning. In all probability both are but electrical phenomena, differing only in the fact that the one is an earthquake, the other a skyquake. It is in plains and valleys that earthquakes prove the most destructive. Doubtless the solid material composing the mountain ranges affords a better conductor of electricity than the alluvial soil of the plains and the valleys; hence, while the one serves as a lightning-rod, the other becomes the battleground of conflicting elements. It may be that electrical forces are generated in the earth's interior, as well as in the atmosphere, and that the earthquake is but the shock produced by the restoration of an equilibrium. The earth and the atmosphere are essentially the same in their elements, and are ever contributing of their substance to the requisitions of each other.