Approximately 150 million years ago, the region near the present-day German town of Solnhofen was a lagoon at the edge of the Tethys Sea. With limited access to open currents, high levels of salinity and shallow water, the area was not suitable to sustain life but the conditions likewise made it ideal for preserving fossils. Over 750 plant and animal species have been found imbedded within the limestone of Solnhofen, mostly of crinoids, ammonites, fishes and crustaceans that drifted in from the ocean or wandered into the region via land, giving a fossilized record of life during the Jurassic Period that goes beyond mere dinosaurs.
Pittsburgh is a long way from Germany, but the Steel City has not one but two collections of fossil-embedded Solnhofen limestone. The first is located at the Carnegie Museum of Natural History, whose impressive assortment of relics includes the preserved remains of pterosaurs, an ancient reptile that was capable of flight and includes the pterodactyl amongst its relations. While Oakland may now be the home of those specimens, meanwhile, fossilized remains of coiled-shell ammonites, sponges, algae and worms can also be found in Ross Township in the most unlikely of places—the floor of Ross Park Mall. It turns out that when the shopping complex was remodeled in the year 2000, the tiles used were imported limestone from Solnhofen that contained noticeable traces of Jurassic Period creatures on their surface regions.