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A chance encounter between determined fishermen and a great white shark off the Tuscan coast in 1666 sparked a chain of events that would help change humans views of fossils and Earth’s geologic past (Cutler 2003, pp. Nicolas Steno (1638-1686) dissected the head of this shark and realized fossil tongue stones believed to be petrified snake or dragon tongues were actually fossil shark teeth (Prothero 1998, p. One problem still existed, how do fossils become embedded in solid rock?
Steno recognized that fossils represent organisms that became buried in sediment, which later turned into rock.
Relative dating uses the principles or laws of stratigraphy to order sequences of rock strata.
Relative dating not only determines which layers are older or younger, but also gives insight into the paleoenvironments that formed the particular sequence of rock.
The secondary rocks were thought to include interlayered basalts, which Werner thought formed by combustion of buried coal layers.
The Scottish geologist James Hutton (1726-1797) argued that granite and basalt by solidification within the earth (as opposed to precipitating in from oceanwater).
Once Steno recognized that the fossils he was contemplating (sharks teeth and sea shells) were formed in the sediments of oceans he was able to work out the basic rules of stratigraphy.
Stratigraphy is a branch of geology that studies rock strata with an emphasis on distribution, deposition, age and evidence of past life.
Nicolas Steno, William Smith, Georges Cuvier, Alexandre Brongniart, and James Hutton developed the basic rules for the science of stratigraphy.
In other words, fossil shells, bones, and teeth were never a part of a living creature! For Steno, the close resemblance between fossils and modern organisms was impossible to ignore.
Instead of invoking supernatural forces to explain fossils, Steno concluded that fossils were once parts of living creatures.
But this explanation could not account for the fact that fossils were not only found on mountains, but also within mountains, in rocks that had been quarried from deep below Earth's surface.