Theory of the Earth was a publication by James Hutton which laid the foundations for geology. In it he showed that the Earth is the product of natural forces. What could be seen happening today, over long periods of time, could produce what we see in the rocks. This idea, uniformitarianism, was a major step in the History of the geologic time scale. It was used by Charles Lyell in his work, and Lyell's textbook was an important influence on Charles Darwin.