Google often does some pretty cool tributes, some of which are highly interactive, some are simply good to look at. Today they are celebrating the 374th birthday of Nicolas Steno, pioneer geologist, palaeontologist, stratigrapher and anatomist (even mineralogist, but let's not go there) before everyone else jumped on those bandwagons.
Not the first to recognise fossil shark teeth as having biological origins, he did lend weight to the idea and correctly thought that they could change composition without losing their distinct shape. He was particularly dedicated to trying to work out how solid objects such as teeth could have ended up in other solid objects like rocks. As this was the 1660s he was really breaking new ground.
His contributions to stratigraphy remain strong. He is credited with formulating the law of superposition, the principle of original horizontality, the principle of lateral continuity, the principle of cross-cutting relationships and even appears to have been aware of faunal succession, all of which are still used in modern stratigraphy (though admittedly expanded upon to an extent).
Although most well known for his geological contributions, he also became a Catholic bishop, involved in the Counter-Reformation, and was even beatified by John Paul II in 1987.
So get on to Google and learn about the man who has paved the way for all of modern geology.