October 5th, 2011


Dinosaurs in the hallways

For years I wondered about the shells in the marble in the hallways of our apartment building. What were they, when did they live? The brownish-cream stone had a lot of them, but I didn't know how to begin to investigate.

Then a friend happened to give me a fossil — and it was a match. I had a Gryphaea obliquata, an extinct oyster common in the Jurassic and Cretaceous Periods.

That clue was enough to eventually identify the exact marble, called Ulldecona stone or Cenia stone, from the town of Ulldecona in Tarragona, eastern Spain. It had been formed in the early Cretaceous Period. At that time, eastern Spain lay under warm, shallow oceans. The shoreline lay close to Castilla-La Mancha, where La Huergina Formation and other fossil beds continue to yield important finds of dinosaurs and other animals.

Now when I wait for the elevator, I stand on the shore of that 130-million-year-old sea.

The oysters under my feet grow in vast colonies. They have two unequal shells, and the heavy curved lower shell keeps them upright on the soft seabed, while the upper lid opens to filter water for food and oxygen. Above them swim fish and ammonites — along with plesiosaurs, which look a lot like the Loch Ness Monster. Do I see one toward the horizon, its long neck arching over the waves?

A forest of ferns and pine trees rises behind me, and off in the distance, a Turiasaurus raises its long neck to munch on a tree. It's a sauropod the size of a small commercial passenger airplane ... safely far away.

Primitive birds, pterosaurs, and insects fly above me, and the buzzes and calls seem familiar. On the ground, frogs and shrews (my ancestors) scurry around.

I hear a heavy rustle. It's geologically too early for T-rex, but a variety of its smaller theropod cousins flourish — the Cocavenator, for example, not exactly a big Velociraptor with quills, but close enough.

Another rustle. It could be the wind in the ferns, a toad hoping after a beetle, or it could be a carnivore edging toward a new, strange prey that seems defenseless and distracted. Then something rumbles in front of me.

The elevator has arrived! I escape into the present. I'm the dominant species now — but the stone under my feet was once alive.

— Sue Burke