James Hutton

James Hutton MD (Edinburgh, (14 June 1726 – 26 March 1797) was a Scottish geologist, physician, naturalist, chemist and experimental farmer. 
Hutton studied in medicine, but never practised it. Instead, he did scientific research, helped to start a chemical industry, and farmed his estate. He is one of the founders of modern geology. He saw the Earth as the product of natural forces. What could be seen happening today, over long periods of time, could produce what we see in the rocks.
His book on the "Theory of the Earth" set out theories of geology and geologic time. These ideas supported the theories of plutonism and uniformitarianism.
Theory of rock formations.
Hutton hit on a variety of ideas to explain the rock strata he saw around him. According to Playfair he "was in no haste to publish his theory; for he was one of those who are much more delighted with the contemplation of truth, than with the praise of having discovered it”. 
After some 25 years of work, his "Theory of the Earth" was read to meetings of the Royal Society of Edinburgh in 1785. 
Hutton later read an abstract of his "Concerning the system of the Earth, its duration and stability" on 4 July 1785, which he had printed and circulated privately. In it, he outlined his theory as follows;
Anticipation of natural selection.
In Hutton's less well-known work is a remarkable anticipation of the idea of natural selection. As always with Hutton, the idea is almost hidden in the complex language:
The same "principle of variation" would influence "every species of plant, whether growing in a forest or a meadow". He came to his ideas as the result of experiments in plant and animal breeding, some of which he outlined in an unpublished manuscript, the "Elements of Agriculture". He distinguished between heritable variation as the result of breeding, and non-heritable variations caused by environmental differences such as soil and climate.
Progress of his ideas.
Hutton's prose hindered his theories. John Playfair in 1802 restated of Huttton's geological ideas (though not his thoughts on evolution). Charles Lyell in the 1830s popularised the idea of an infinitely repeating cycle (of the erosion of rocks and the building up of sediment). Lyell believed in gradual change, and thought even Hutton gave too much credit to catastrophic changes. 
Lyell's books had widepread influence, not least on the up and coming young geologist Charles Darwin who read them with enthusiasm during his voyage on the "Beagle". William Whewell coined the term uniformitarianism to describe Lyell's version of the ideas. This was in contrast with catastrophism, the idea that the rocks recorded a series of catastrophes followed by repopulation by a new range of species. Over time there was a convergence between these views, but Lyell's description of the development of geological ideas led to a belief that uniformitarianism had triumphed.