Sunday, July 8, 2012
When I took a geology class in college, one of our field trips was to a place where we could see fossils. The Teaching Assistant who lead our group asked if we had any questions. I asked why fossils form sometimes but not all the time. The poor TA tried to gobbledygook me with polysyllabic words.
The fact is that sometimes sediment falls on a dead animal, or even a live one (killing it) in such a way that the skeleton is preserved. And most of the time, the animal’s carcass simply falls to the bottom of the ocean or lake, where the flesh is eaten by animals and bacteria and the bones disintegrate over time.
Most of the time footprints are washed away, but sometimes they get preserved. It’s random. We’re lucky to have any fossils at all.
I recalled this I saw fossils when I was walking to the gym. Not preserved in stone, like the ones we saw on that field trip. Rather, they were preserved in cement. Quick drying sidewalk cement.
An archeologist would learn a lot by looking at these sidewalks. Birds, dogs and shoe-wearing humans have left their marks. I’m sure there were signs and barriers in place, trying to prevent these fossils from occurring. But the birds and dogs can’t read and the humans ignored them. So, again, why do fossils happen some times, but not all the time? It’s random.