I suggest, then... that the first step was an advance under favor of peculiar conditions, from the simplest forms of being, to the next more complica… - Robert Chambers

The earliest stratified rocks contain no matters which are not to be found in the primitive granite. They are the same in material, but only changed into new forms and combinations; hence they have been called by Mr. Lyell, metamorphic rocks. But how comes it that some of them are composed almost exclusively of one of the materials of granite; the mica schists, for example, of mica—the quartz rocks, of quartz, &c.? For this there are both chemical and mechanical causes. Suppose that a river has a certain quantity of material to carry down, it is evident that it will soonest drop the larger particles, and carry the lightest farthest on. To such a cause is it owing that some of the materials of the worn-down granite have settled in one place and some in another. Again, some of these materials must be presumed to have been in a state of chemical solution in the primeval seas. It would be, of course, in conformity with chemical laws, that certain of these materials would be precipitated singly, or in modified combinations, to the bottom, so as to form rocks by themselves.

Just suppose for a moment that every fact reported to us by others were viewed in the light of the skeptical system, as to the fallaciousness of the senses and the tendency to self-deception. Should we not from that moment be at a stand-still in all the principal movements of our lives?

This skeptical method consists very much in vicious circles. You cannot know whether a fact be a fact till you have ascertained the laws of nature in the case, and you cannot know the laws of nature till you have ascertained facts.