Google Rocks

I love the Google homepage logo for today! It's not often that you see geology incorporated into internet art. Curious about what inspired the geo-drawing I did a little research, and found out that today is the 374th birthday of Nicholas Steno the founding father of the geological sciences.
Back in the 1600's in addition to realizing that fossils were the remains of animals that no longer existed (I guess at the time people thought they were left over from the flood?), he also discovered the three of the primary laws of geology which remains uncontested today.
The law of original horizontality states that all sedimentary rock layers originally form horizontally, and are only tilted later. The law of superposition states that the material in the lowest layer is older than the material in the upper layers. And the law of discontinuity states that if one object or rock layer cuts another than the layer that is cut is older than the one doing the cutting.
So, thanks Nick for all your great observations and starting my specific branch of science! You rock! (ha ha get it?)