Nicolas Steno and the Principles of Modern Geology.
Niels Stensen - 1686. In January 1638 Danish Catholic bishop and scientist Nicolas Steno was born. He was both a pioneer in both anatomy and geology and seriously questioned accepted knowledge of the natural world. Importantly he questioned explanations for tear production, the idea that fossils grew in the ground and explanations of rock formation. By some he is considered the founder of modern stratigraphy and modern geology. Nicolas Steno was born as Niels Stensen but is better known by the Latinized form Nicholas Steno. He was a native of Copenhagen but left Denmark around 1660 intending to study medicine at the University of Leiden. His studies of anatomy which he continued in Paris Montpelier and Florence attracted the attention of the Grand Duke of Tuscany, Ferdinand II who appointed appointed Steno to a hospital post that left him time for his research. . At first, Nicolas Steno's studies were focused on the muscular system as well as the nature of muscle contraction. When around 1666 fishermen caught a shark near Livorno Duke Ferdinand ordered his head to be sent to Steno who dissected it and published the findings one year later. He noticed the resemblance of the shark's teeth to certain stony objects found in rocks. As most contemporary scientists argued differently, Steno believed that these 'stony objects' looked so much like shark teeth because they actually were shark teeth. Well, Steno was not the first who linked these so called 'tongue stones' with shark teeth. For instance, already Robert Hooke and John Ray argued that fossils were the remains of living organisms Important is however, that Nicolas Steno came to realize that it was not clear yet how how any solid object could come to be found inside another solid object like a rock. In 1669 he published a paper on the topic with the title 'De solido intra solidum naturaliter contento dissertationis prodromus'. . Nicolas Steno stated that a solid object will cause any solids that form around it later to conform to its own shape. Thus, the famous 'tongue stone' must have been buried in soft sediments which hardened later while crystals must have formed after the surrounding rock was a solid, because they often showed irregularities of form caused by having to conform to the surrounding solid rock. His further conclusions are now referred to as Steno's law of superposition It means that layers of rock are arranged in a time sequence, with the oldest on the bottom and the youngest on the top, unless later processes disturb this arrangement. Steno also mentioned that rocks may be uplifted by subterranean forces. Steno also made efforts to distiguish different time periods in the Earth's history, which would develop more accurately in the work of later scientists. . Nicolas Steno was ordained as a priest in 1675 and essentially abandoned science. He became a bishop a few years later and spent the rest of his life ministering to the minority Roman Catholic populations in northern Germany Denmark and Norway . At yovisto, you may learn more about 'What can Fossils teach us' in a video lecture by Paul Sereno.