YOU CAN WALK FOR A MILE ON THE BOTTOM OF THE DEVONIAN SEA, directly across the Ohio River from Louisville, Kentucky. Almost four hundred million years ago patch coral reefs stretched beneath shallow tropical waters for a thousand miles across what is now Midwestern America. For thousands of years coral built up, sediment accumulated, and the life of the reefs flowed and ebbed and passed away. Millennia after millennia the continents pulled, stretched, cracked, melded, fell, and rose. At cataracts called the Falls of the Ohio the river cut through the eons of sediment and crust to the primeval rock, revealing the fossils of massive colonial corals—some six feet across, horn coral, brachiopods, bryozoans, crinoids; all frozen in stone. When the water is low several acres of coralline limestone beds—the ancient ocean floor—are exposed. The stone swirls in low arabesque relief, through imagined channels, as though the sea itself has been fossilized. Yet it is not the stone by itself that compels your attention, but the remains, the reminders, of life the stone holds. Your eyes take in the modern city skyline across the river while your feet below take you into a distant past. Walking through, touching, seeing this once-living coral sea transports a great Drama of God’s acts across deep time.
Most of the fossils of the Falls of the Ohio beds are sessile organisms—creatures that grow like gardens attached to sea floor, to rocks, or to one another. Only occasionally might you find bits and pieces of the motile marine species of the Devonian era—lungfish, lobefins, placoderms, early nautiloids, and the trilobites. But they were all there, long ago. Especially the trilobites—lots of trilobites.
TRILOBITES ARE EXTINCT MARINE ARTHROPODS that looked something like a pill bug or wood louse. They came in a multitude of species, from the largest, the 30 inch Isotelus Rex, to the millimeter-sized Acanthopleurella. They emerged suddenly in the fossil record during the Cambrian Explosion over 500 million years ago and endured for nearly 300 million years. “Emerged” is the right word to use because there are no evolutionary predecessors to the trilobites in the fossil record. Nor are there any evolutionary predecessors to any of the organisms in the fossil record of the Cambrian Explosion. Richard Fortey, senior paleontologist at the Natural History Museum in London, and hardly a biblical creationist, wrote, “It is as if the players in the Cambrian Drama had appeared from somewhere else, having dressed and made up in secret. Where are the late Precambrian brachiopods, molluscs [sic], echinoderms and arthropods that might have provided the Prologue?” Fortey doesn’t really answer that question. He assumes a common ancestor for the trilobites and goes on from there (his book, Trilobite! Eyewitness to Evolution is still a fascinating read). But trilobites were already complex, segmented creatures, with a head and tail, antennae, and compound eyes, and they were already just there.
THE EYE OF THE TRILOBITE was an especially interesting aspect of its “dress and make-up”. It is nearly the earliest eye in the fossil record, it too has no predecessors or intermediate forms, and it is already a complex masterpiece of bio-engineering. Nuclear physicist and trilobite expert, Riccardo Levi-Setti, called the trilobite eye an “all-time feat of function optimization.” (For the details, there is short BBC video here: http://www.bbc.co.uk/nature/life/Trilobite#p00ckq2f; and a technical monograph here: http://www.asa3.org/ASA/PSCF/2000/PSCF12-00Chadwick.html)
Trilobite eyes were compound—somewhat like modern insects—and the most prevalent type, called a holochroal eye, consisted of hundreds, even thousands, of biconvex lenses. The complex design of the focus resolving mechanism in these lenses resembles those in modern camera and telescope lenses. And this is not even to mention the complex nervous system required to make such an eye fully functional. Arthur Chadwick concludes that, “When such a biconvex lens is found in nature, logic demands that intelligent design is a required element in the explanation of its formation.”
Perhaps the role of the trilobites, ubiquitous as they were, was only as bit players or even extras in the great Drama of creation. Yet large plot developments in a story often hinge on such seemingly insignificant actors. We can only marvel at the Author who lavishes such imagination and creativity on even the least of the details of his great Drama.
Next week: The Rime of the Ancient Trilobite – Part 2: Death, Be Not Proud