I spent yesterday morning volunteering at the Virginia Living Museum. Usually I volunteer in the observatory, showing off sunspots and solar prominences with a telescope. But on rainy days like this, I go inside and work in the Virginia Underground exhibit. This exhibit includes a section on the fossils of the Yorktown Formation, which I’ve written about in previous entries about fossil beaches at Chippokes Plantation and York River State Park.
The first thing that most people notice coming into the exhibit is a large aquarium full of tropical fish. Since the VLM is a popular field trip destination for elementary school groups, I soon learned that the fish I refer to as clownfish and blue tang are known to a younger generation as “Nemo” and “Dory.” But what, they may wonder, does that have to do with Virginia Underground? Coral and tropical fish are not native to Virginia, nor are they underground. Or are they? Virginia was not always as we see it today. From 5 to 3.5 million years ago, when the sediment of the Yorktown Formation was being laid down, this region was covered by a warm, temperate sea. The remains of its denizens are now embedded in the banks of the James River and elsewhere in the Chesapeake Bay region. A re-creation of a local riverbank stands next to the aquarium, studded with fossils to present a before-and-after picture. The coral and manatee bones indicate that the temperatures used to be warmer here. Fossilized whale bones indicate that the water was deeper.
A giant shark’s tooth is the most impressive fossil, indicating that the monstrous Carcharodon megalodon used to live hereabouts. A note that this shark was the size of a school bus helps to make the point with the youngsters. I could imagine a bus load of my grade school classmates being swallowed up by this hideous behemoth: the bully who stole my lunch money; the guys who chose me last for the baseball team; the girls who thought, however correctly, that I was a nerd – gone in a single gulp. I suppose it’s past time to let all that go, though I must admit the brute efficiency of the idea does appeal to my prediliction for tidiness. But not to worry, megalodon died out in these parts 4 million years ago and we now have only shark’s teeth scattered along the riverbanks to remind us who once ruled the local waters.