Plenty of us wanted to be paleontologists when we grew up, but most never got a chance to realize that dream. Little did we know, however, that right beneath our feet, caches of urban fossils were just waiting to be discovered.
An "urban fossil" is exactly that: a recognizable fossil hiding in plain sight among city architecture, such as buildings, roads, and monuments. Here in the United States, for example, our capital is chock full of them. You can spot all manner of organisms peppering the walls, lobbies, and steps of Washington, DC's grandiose architecture.
For many people, fossil hunting has become a bit of a sport. "There are fossils all over the place, and most people don't know about them. But once you know what to look for, they're everywhere," Christopher Barr, a lawyer and urban fossil sleuth told the Washington Post earlier this year. And, as the saying goes, one you see them, you can't unsee them.
In 2015, a geologist in Girona, Spain stumbled upon a spectacular find in the city's limestone streets. A collection of bones, appearing to be parts of a creature's skull and spine, were clearly embedded in the pavement. What this unsuspecting pedestrian had discovered were the fossilized remains of an ancient sea cow, possibly belonging to the extinct genus called Prototherium, according to the Society of Vertebrate Paleontology.
When photos of the fossils were submitted to Paleourbana, an online forum dedicated to this sort of thing, paleontologists Manja Voss and Oliver Hampe from Berlin's Museum für Naturkunde were able to identify it. The local find was deemed important enough to remove from the pavement (with permission from the city), which allowed the researchers to analyze it using a CT-scan. As it turns out, the limestone rock comprising the slab was some 40 million years old, making Girona's sea cow one of the oldest known specimens in Europe.
"While the limestone used to build the city of Girona are enriched by fossils—it is quite common to identify invertebrates for example—finding a marine mammal on which thousands of people walked over for the last two decades is indeed very peculiar," Voss said in a statement this week.
So for anyone feeling that childlike-wonder again, here are some of the coolest accounts of architectural fossil finds to date. The list is constantly growing, so if you try hard enough and believe in yourself, maybe you too can become the Indiana Jones of urban fossil hunting.
Possible "marine reptile" bone: St. Margaret's, Westminster, London, UK
Fossil mix including brachiopods: United States Botanic Garden, Washington, DC, US
According to the website Fossils and Other Living Things: "The Botanic Garden is located just southwest of the U.S. Capitol Building, next to the Capitol Reflecting Pool. It is constructed of gray and beige Indiana limestone. Its patio is made of reddish orangey Pennsylvania sandstone. Needless to say, it was the limestone exterior walls that drew me since they held my quarry. The limestone is clearly nearly all fossil… One of my special finds on this hunt was this relatively large brachiopod shell enmeshed in an oblong lens of finer grains of shelly material."
Ossicles from "sea-lillies" and bryozoans: Capitol Reflecting Pool, Washington, DC, US
Also from Fossils and Other Living Things: "The pool and its steps are made of Indiana limestone… The limestone steps are awash with the ossicles from crinoids. Ossicles are the round segments that make up the stems or stalks of crinoids, so-called "sea lilies," which are invertebrate animals, not plants at all. These little disks are typically all that remains…. The fossil tapestry of the steps includes the latticework remnants of the structures built by colonies of bryozoans, tiny invertebrates who lived in chambers within the upright branches. The structures can consist of relatively thick interconnected branches."
Ammonite shell fossil, approximately 150 to 160 million years old: Reptile House, Smithsonian's National Zoo, Washington, DC
In an interview with the National Building Museum, DC's resident fossil hunter, Christopher Barr described his favorite findings: "The entrance to the Reptile House at the National Zoo is framed with a stone from Spain that is Jurassic in age and displays the shells of squid-like animals, ammonites and belemnites, directly under a mosaic of a Jurassic-era dinosaur (Stegosaurus). It was designed by the noted artist Charles Knight, who worked on the Reptile House shortly after studying in Spain. Is that likely to be a coincidence? Also, the use of "Champlain Black" stone, with its large, visible snail fossils in the floor of the Arts and Industries Building, which was the Smithsonian's first museum of, among other things, natural history, may not have been accidental."
Fossilized oyster shells: St. John's Smith Square, London, UK