We come now to that which has built up so rapidly this empire of the Pacific--the metallic and mineral wealth of California. As to the extent of the region, and indications of the existence of the gold, together with the attendant geological formations, the statements of Mr. King's report will not be, nor have not been, gainsayed; but as to the origin of the gold, whether in combination with quartz, or mixed with the sands of the ravines and streams, various opinions have been expressed by those who have spent considerable time in working and observing the different formations. That due weight may be given to both of the principal theories, we extract the observation and opinion of a person who favors the idea of the gold having been scattered over the country, by a tremendous volcanic eruption. "The gold found in every placer in California bears the most indubitable marks of having, at some time, been in a molten state. In many parts it is closely intermixed with quartz, into which it has evidently been injected while in a state of fusion; and I have myself seen many pieces of gold completely coated with a black cement that resembled the lava of a volcano. The variety of form, which the placer gold of California has assumed, is in itself sufficient evidence of the fact, that it has been thrown over the surface while in a melted state. The earliest comparisons of the California gold were to pieces of molten lead dropped into water. The whole territory of the gold region bears the plainest and most distinct marks of being volcanic. The soil is of a red, brick color, in many places entirely barren, and covered with a flinty rock, or pebble, entirely parched in the summer, and during the rainy season becoming a perfect mire. The formation of the hills, the succession of gorges, the entire absence of fertility in many portions, distinctly exhibit the result of a great up-heaving during past times. But there is one phenomenon in the mining region which defies all geological research founded upon any other premises than volcanic formation. Throughout the whole territory, so generally that it has become an indication of the presence of gold, a white slate rock is found, and is the principal kind of rock in the mining region. This rock, instead of lying as slate rock does in other portions of the earth, in horizontal strata, is perpendicular, or nearly so; seeming to have been torn up from its very bed and left in this position. On the banks of the Middle Fork are several excavations, which can only be accounted for upon the supposition, that they were at some time volcanic craters. There is one of these on the mountain side, about five miles below the "Big Bar;" from which, running down to the base of the mountains, is a wide gorge entirely destitute of verdure, while the earth around it is covered with shrubbery. This, I am fully convinced, was the bed of the lava stream that was thrown up from the crater; and in searching for gold at the