I have already compared the dump to a rampart, built certainly by some rude people, and for prehistoric wars. It was likewise a frontier. All below was green and woodland, the tall pines soaring one above another, each with a firm outline and full spread of bough. All above was arid, rocky, and bald. The great spout of broken mineral, that had dammed the canyon up, was a creature of man’s handiwork, its material dug out with a pick and powder, and spread by the service of the tracks. But nature herself, in that upper district, seemed to have had an eye to nothing besides mining; and even the natural hillside was all sliding gravel and precarious boulder. Close at the margin of the well leaves would decay to skeletons and mummies, which at length some stronger gust would carry clear of the canyon and scatter in the subjacent woods. Even moisture and decaying vegetable matter could not, with all nature’s alchemy, concoct enough soil to nourish a few poor grasses. It is the same, they say, in the neighbourhood of all silver mines; the nature of that precious rock being stubborn with quartz and poisonous with cinnabar. Both were plenty in our Silverado. The stones sparkled white in the sunshine with quartz; they were all stained red with cinnabar.