If you’ve ever spent time at the beach on the Gulf Coast of the United States, it isn’t hard to picture the scene I saw recently. Put on your imagination goggles, and follow me.
My friends and I were hiking in the hills of North Alabama the other day, yet at the same time we were submerged in warm ocean waters that rose a hundred or so feet above us as we stood on the shelf extending hundreds of miles to the south and west.
Things appeared relatively peaceful here in the waters of north Alabama. The gentle currents caused the animal life to sway from side to side, aiding their feeding efforts. These animals, crinoids, Archimedes, and blastoids, were mostly immobile, anchored to the ocean floor much like coral.
Their appearance was unlike coral, though, as the structures they used for capturing food looked almost like ferns or fronds, held away from their bases by long, narrow stalks. They ate plankton, detritus, and microscopic creatures that drifted into the pinnules of their mesh-like feeding structures.
Breaking the calm, sharks and fish swam the waters, the hunters and the hunted. Squid-like animals–cephalopods–were plentiful as well, moving through and around the creatures anchored in place. Time passed slowly in the Alabama waters. Animals were born, reproduced, and died there, their bones and other calcium-rich structures falling to the ocean floor.
Falling to the ocean floor, in layer after layer as the years, centuries, and millennia came and went. Compressing under the pressure of the higher layers and the ocean water above, eventually forming the limestone we walked upon early in the twenty-first century, anno domini.
As we walked among the creeks and hills, we were able to find a record of those days some 300 million years ago. Fossils were plentiful: pieces of crinoids, blastoids, Archimedes, and various cephalopods. With a bit of imagination, it was just a day at the beach, well, I should say “off the beach,” Pennsylvanian period style.