This site provides information about Nicholas Steno, the Father of Stratigraphy, whose work on the formation of rock layers and the fossils they contain was crucial to the development of modern geology. The principles he stated continue to be used today by geologists and paleontologists. Steno along with contemporaries Robert Hooke and John Ray was able to link tongue stones with sharks teeth and thus argued that fossils were the remains of once-living organisms. This lead to the eventual development of the principle of original horizontality and the law of superposition.