Although modern geology appeared in the eighteenth century, the Earth was already studied by the Greco-Roman philosophers. The Greek philosopher Theophrastus (371 to 287 BC) described and classified minerals according to their physical properties. The Roman writer Pliny the Elder (23-79 AD) described minerals, crystals and fossils. Also some medieval Muslim scholars proceeded in the field of geology. Al-Biruni (973 – 1048) described the geology of the Indian subcontinent and believed this area was once a sea. Avicenna (981 – 1037) described the formation of mountains as an interplay between tectonic forces and erosion . He believed that mountains had made this form which aproved that the Earth is very old. The Chinese scholar Shen Kuo (1031-1095) independently came to similar ideas.
In Europe one of the first naturalists was Leonardo da Vinci (1452-1519). Da Vinci understood that the fossil shells that he found in the Apennines are indeed remnants of life from earlier times. The Venetian physician Georgius Agricola (1494-1555) was particularly interested in the mining industry. He shared the first rocks in a methodical way: in four groups of consecutive age and consolidation. Nicolaus Steno (1638 – 1686) investigated how rock layers are formed and proposed three laws, with which he was the founder of the stratigraphy.
As the first modern geologist is considered James Hutton (1726 – 1797). In 1785 he presented an article entitled Theory of the Earth to the Royal Society in Edinburgh. In this article he described his theory that the Earth must be much older than what they previously assumed, there had to have gone over much longer time for mountains to erode, and sedimentary rocks to form at the bottom of the sea.
Followers of Hutton were known as plutonisten because they believed that many rocks were formed by volcanism, the solidification of lava or magma, as opposed to the neptunisten who thought that all rocks beaten down over the ocean where the sea level gradually decreases.
William Smith (1769 – 1839) drew the first geological maps and began organizing strata (layers) by examining the occurring fossils .
Charles Lyell wrote the famous book Principles of Geology, first published in 1830, but until his death in 1875 constantly being revised. He introduced the doctrine of uniformitarianism. This theory suggests that slow, gradual processes was shaping the Earth’s surface, and still does the work. In geology, this theory has been accepted by the catastrophism, which said that the surface of the Earth was formed in short, catastrophic episodes, but in between virtually unchanged.
The theory of continental drift was proposed by Alfred Wegener in 1912 but it took 60 years of the twentieth century until the theory of plate tectonics was designed and generally accepted.

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