Hutton formally proposed later on. James Hutton: Proposed plutonism to the scientific community. At prior to being a scientist, he was a farmer in Scotland. He utilised his experiences of when he was farming to identify natural forces – notably gravity – contributing to the formation of rocks, as the Earth's landscape would slowly erode and deposit on lower planes. He first conducted his formal observations in Scotland, specifically at Glen Tilt of Perthshire, but made informal observations through his time as a farmer prior to becoming a geologist, noticing how the land he was farming was experiencing changes at a slow rate through aspects such as erosion and the deposition of sediments. He is regarded as “the Father of Geology”, as his work is present as core concepts within the uniformitarianism theory that became the widely accepted geological theory in the 1830s that ended the debate of whether plutonism or neptunism was the “correct” theory. John Playfair: a natural philosophy professor who published Illustrations of the Huttonian Theory (1802) and shielded Hutton from opposition by neptunists. This allowed Hutton’s work to not simply disappear in the abyss of scientific hypotheses and proposed theories, ensuring that other scientists would be able to notice Hutton’s theories. Playfair’s work led to Lyell being more able to uncover the existence of such theories, which he then implemented within uniformitarianism to end the geological schism. Charles Lyell: a scientist who is credited as being “one of the most important scientists of geology in the 19th century”, due to founding uniformitarianism, which has been the widely accepted geological theory after the 1830s. His theory incorporated Hutton’s plutonism as core principles, which lead to a de facto acceptance of plutonism over neptunism. His theory, however, was competing with the theory of catastrophism, which accepted neptunism as part of its core concepts. Though at the time, uniformitarianism became more accepted, current scientific thinking now accepts that aspects of both theories are true for the general formation of the current landscape observed on the Earth. References History of Science: Early Modern Geology . . . And Still We Evolve, A Handbook on the History of Modern Science, Ian Johnston of Malaspina University-College, Nanaimo, BC. (public domain) 18th century in science History of Earth science Obsolete scientific theories