This in honor of Nicholas Steno's 374th birthday. I know that is a milestone I will be looking for in my own life. For those that don't know who he is not the guy named on the buffet line heating cans. That's Sterno:
Steno is one of the founders of modern geology. If modern geology has giants in it's past, Steno would be one of them. He defined the main laws of stratigraphy including the Law of Universal Horizontality (rocks were deposited horizontally) and the Law of Superposition (Rocks on top are younger than rocks below, this also applies to faults and other events). He is a name to know for all geology students to show that even though things seem obvious to us now-a-days, it was not always this way.