Google has a doodle up today, celebrating the 374th birthday of geologist Nicolas Steno.

Though he is known as one of the founders of both modern stratigraphy and modern geology, his scientific contributions have also lent themselves to paleontology, crystallography and even anatomy (he is credited with the discovery of the duct of the parotid salivary gland) in the heads of dogs, rabbits and sheep.

In stratigraphy, he’s credited with the law of superposition, the principle of original horizontality and the principle of lateral continuity.

He is perhaps known best for his work with fossils and figuring out that rocks that were shaped like shark teeth were actually fossilized shark teeth.

By the way, Google is also advertising “Search plus Your World” on Google.com, as you can see in the lead image.