Having giving this brief description, I will now proceed to what may be called theory—that is, _facts derived from induction_. Let us suppose a series of horizontal strata, one above another, but of unequal depth, incumbent on the original unstratified mass, which forms the nucleus of the globe. According to geologists, this was the natural position. Now, in consequence of some powerful volcanic agency, the lower mass is thrown up from below, and becomes the nucleus of a mountain, and that which was before the lowest, now appears at the top, while the various strata which lay flat upon it are tilted up on its sides. These being cut through, in the manner described, there is exposed to view in these cuts, the various strata and their contents, in the same manner as if a shaft had been sunk through them in their horizontal position. If there be any metallic seams to the right or left of these cuts, they will be seen like threads, and running lengthwise with the range of mountains. The metals contained in the now vacant spaces of these ravines, have been carried away and deposited below. The masses, thus broken and separated, have been still further reduced in the manner before stated, greatly diminishing the labor of mining. The deposits of detritus intermixed with gold may be the work of thousands of years; but the quantity may be estimated by the number and width of the natural cuttings through the gold seams now disconnected. It is certain that the amount of gold at the bottom cannot exceed the amount carried down from these original deposites. Without assuming that the amount of gold deposited in the Sierra Nevada is actually greater than in the same range further south, its peculiar geological and geographical character, may be a reason why gold may be _found_ in California in greater abundance than in any other part of the world. It is found along this whole range from Sonora to Chili, although in greater or less abundance; and there is no doubt that a variety of other metals will be met with, perhaps as valuable, when the passion for gold washing shall have somewhat abated. It is remarkable that gold has been found almost invariably on the western or Pacific side of the great range, while silver, copper, and lead are discovered on the eastern side, and at a much greater elevation. It is probable that, instead of gold; silver and copper exist on the eastern side of the Sierra Nevada, towards the great Basin. What a field for the mineralogist!