Wednesday, October 16, is Fossil Day. The National Park Service proclaims it so, now for the tenth year. Its stated mission is “to highlight the scientific and educational value of paleontology and the importance of preserving fossils for future generations.”

As far as I know, there are no parades, costumes, holiday cards, or festive foods, just a day to appreciate stone bones. Special events are taking place at natural history and science museums in at least 34 states; but at this late date, you may have already made other plans, so at least you should know what paleontology is as well as what fossil are and a little bit about how they form.

Paleontology, a blending of geology and biology, is the study of ancient life on Earth, based on fossils, which are stone replicas of plants and animals.

An animal may die and get silted over before its skeleton either weathers away or gets scavenged. When conditions are just so, water permeating through those bones’ porous surfaces and leaches out calcium-containing molecules, which are then immediately replaced by another mineral dissolved in the water. The bone turns to stone, one molecule at a time, over tens of thousands—sometimes hundreds of thousands—of years. The mud surrounding the bone also turns to stone, but its constitution is different because it did not start out as bone. If the fossilized bone weathers away a little more slowly than the sedimentary rock within which it is embedded, then later—even millions of years later—when a sea, lake, or riverbank dries up, a passerby might spot a partially exposed fossil.

I get brain freeze when I consider two probabilities. First, only a tiny fraction of animals from millions of years ago were successfully transformed into fossils. Second, most of those that did turn to stone are either still buried or have already become exposed and have weathered away. The fossils that we do have, therefore, constitute only a minuscule glimpse of ancient life, yet they provide fortuitous and miraculous insights into Earth’s history. It is worth a day of reflection.

The public’s interest in fossils had a distinct beginning date–1868. Before that, large stone bones, which as you can imagine are heavy, collected dust in university and museum storerooms.

British artist Benjamin Waterhouse Hawkins was a prolific and well-known natural-history illustrator for Darwin and other mid-century biologists. Hawkins was commissioned to develop an extensive “Paleozoic Museum” in New York City’s Central Park. The intention was to dynamically display dinosaurs that had recently been discovered in America.

Because New York neither possessed the necessary fossils nor the paleontological expertise for the project, Hawkins ventured to Philadelphia. There he received support from the Philadelphia Academy of Natural Sciences to assemble the skeleton of a thirty-foot dinosaur, most of the bones of which were in the Academy’s collection. He made plaster reproductions of missing bones and creatively supported them all with a metal framework such that the reconstructed skeleton assumed a lifelike, standing posture. Hawkins was the first to display fossilized dinosaur bones in this manner.   

The public clamored to see this assembled dinosaur skeleton. Attendance at the Academy doubled over the next year. The display piqued the public’s interest in dinosaurs, an interest that remains strong over 150 years later.

If you need some other juicy facts to spice up your Fossil Day conversations, here are several previous About Bone posts that will help.

Genuine Hate Produced the Bone Wars

T rex Rocks

Fossil Fraud Foisted, then Fossil Fraud Foiled

And finally, a little paleontology humor. We wouldn’t understand if we didn’t have fossils. Happy Fossil Day.