By Eric Burnette
Photos by Mickie Winters
Look up. To the top of your house. To the top of the trees. Maybe even to the top of your downtown office building. All of this was underwater. Warm, tropical, equatorial water, something like the Bahamas today. You are living, sitting, working on the bottom of a sea that is no longer here.
Hundreds of millions of years ago, the Paleozoic seas once stretched across much of what is now the southern and midwestern United States. The seas were full of life — brachiopods, corals, sponges, plankton, trilobites, coelacanths, cephalopods, primitive sharks and fish, snails. My first inkling of this ancient past came about 10 years ago, when I was walking on the limestone wall along Park Boundary Road in Cherokee Park. I noticed bits of coral in the rock, sometimes quite well preserved. I made a mental note but didn’t really try to understand what I was seeing.
Then, this past January, news broke that a dinosaur expert had discovered a Rosetta Stone of Cretaceous animal tracks — dinosaurs and pterosaurs and even mammals — next to the parking lot (the parking lot!) at NASA’s Goddard Space Flight Center in Virginia. He’d been visiting his wife for lunch. This followed the unveiling last year of a spiky ankylosaur found in Canada, so well preserved that it looked flash-frozen.
I began to wonder: What do we have under our feet?
Chain coral in Cherokee Park.
A lot, as it turns out. Around here, fossils are everywhere. Creek beds, rock walls, natural pavers. Ornamental boulders outside the bank, outside the library, outside the Louisville Zoo. Even limestone gravel can contain fossils up to 425 million years old. “Most people have very little idea how old these are,” says Jafar Hadizadeh, professor of geography and geosciences at the University of Louisville. “They literally kick it around.” It can be hard to wrap your brain around a number as big as 400 million. Think of the entire populations of the United States and Canada lined up single file. We would stretch to the moon and back. That many years ago.
Hadizadeh’s office is on U of L’s main campus, off to the side of Lutz Hall’s monumental arched lobby. It’s more cozy than grand, a little nook of books and minor artifacts, things students bring to him. He has silver hair, a silver goatee and olive skin. “Paleontologists,” he says, “read rocks like books, except that the pages are in layers of rocks.” The story these rocks tell is one of great changes happening very slowly. Over 300 million years ago, he says, “This is a tropical, reef-like environment. We’re talking about Florida.” And actually, he explains, due to plate tectonics and continental drift, this place itself — where you are sitting right now — would have been hundreds of miles away from here, closer to the equator.
Hadizadeh grew up in Tehran, Iran, which he says is Denver-like in its geography. The family’s apartment was small, but when they went out on a hike everything was wide open. “My uncle was…a curious guy. He would stop and take a piece of rock. I kind of followed his lead. I got curious about what he was curious about.” A volcanic rock was the first to grab Hadizadeh’s attention. Recalling it, he gets the look of somebody remembering something dear from childhood, like your first bike or first puppy or first tree house. His eyes smile. “I had very little idea of where it had come from or what it was. But then when I was doing my Bachelor of Science in geology, I went back to the same mountain to do my undergraduate thesis. Then I learned about it.
“It’s interesting,” he says. “I can go back to it and back to it and back to it and dig into it. In fact, I remember more about that time than I do about yesterday.”
Geology is time travel. As I climb down into the gulch, time doesn’t slip away so much as break. Eons crumble beneath my feet. It is pouring rain.
Harrods Creek in Oldham County has carved away 100 feet of earth, leaving layer upon layer exposed. They tell the story of tens of millions of years, cycles upon cycles, water, land, plants, compression, shale, stone, water returning, water leaving again.
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| Michael Popp's trilobite. |
Trying not to slip on the wet ledges, I poke around and look for obvious fossils. And then, I realize, they really are everywhere. Mostly shells about the size of a quarter or half-dollar. Little brachiopods, looking not so different from the clams in Harrods Creek today (although, they are, in fact, completely different, simply evolved to look similar). I find one freestanding brachiopod, almost perfectly preserved in limestone. It has a distinctive bell curve for a mouth, which identifies it as the Hebertella brachiopod. This is my favorite little guy.
Fossilization is a molecular process. It usually starts when a plant or animal gets buried in sand or mud (in this part of the country, fossils were made from what got buried at the bottom of the sea). Over time, more layers of sediment pile on top. Pressure builds. And, gradually, the molecules of the plant or animal (or, as is often the case, the mud inside the animal’s shell, which can outlast the shell itself) are replaced by molecules of stone or crystal, leaving a decent facsimile made of different matter. It’s like a magic trick that takes millions of years to play out.
At Harrods Creek, bits of coral stick out here and there. There’s limestone stained a rusty-gold color by the soil, highlighting the dark faces of clam-like brachiopods. Other shells peak out of the shale, which, like coal and oil, is made from mud and the compressed remnants of plant matter. If you take a piece of shale and break it open, you can see outlines of shells inside. The shale is brittle, and it’s hard to get a piece out with a shell intact, but finally I do it. I put a few black shells in my bucket and keep moving. Later, I will drop one on my porch and break it in half, unceremoniously ending 400 million years of preservation.
Fossilization has carried these ghosts of little creatures into the future. But now that they are exposed, the fossils are eroding. Time is carrying even the ghosts away.
The creek gushes by. Chimney swifts swirl overhead, and the song of a wood thrush pings off the canyon walls. Soaked to the bone, I finally climb back through time, into the modern world.
Like Hadizadeh, my most personally significant fossil finds are in the same place where I first became aware of geology — rock walls in Cherokee Park. There are two separate walls, each capped with large limestone slabs, presumably quarried nearby when the park was built in the 1890s. One goes along Beargrass Road, between the pavement and the creek, the other along Park Boundary Road, above the creek on the other side. I spy coral after coral, great in their variety and size — some as big as an end table. Honeycomb corals, pipe-organ corals, horn corals and branching corals. Colonies of hexagonal Phillipsastraeidae, in which each little animal built its own home next to the others, like barnacles on a pier. But my favorites are the nautiloids. These were cephalopods, relatives of the modern squid and octopus, some of the most intelligent creatures on the planet. There’s a straight nautiloid on the Beargrass Road side, its shell about two feet long — long and narrow, like an artillery shell. Its squid-y tentacles would have come out of the end.
And then, almost exactly above Big Rock, is my best find — an ammonite about the size of a bread plate. Ammonites are ancestral cuttlefish, like a squid with many arms, coming out of a nautilus-shaped shell. Even now, you can see the spiral of the shell and imagine this creature swimming near here before it got buried in the sand, forever.
But, of course, not forever. The fact that I can see this fossil means it is slowly weathering away.
The morning fog hangs close to the ground as the sun begins its ascent, lighting it up. The air glows like alabaster.
In a very specific way, Louisville is here because of geology. The Falls of the Ohio were where the Ohio River ceased to be navigable. River traffic would have to stop, unload and reload (a problem the McAlpine Locks and Dam eventually solved). Geology was our destiny.
The Falls are still one of the best and oldest exposed fossil beds in the region. After good rains, there is ocean-like power in the water at the shoreline of the Falls of the Ohio State Park, in Clarksville, Indiana, where one slip into the current could sweep you away, perhaps for good. “The fossils are here as long as the river lets us take a look at them,” says Alan Goldstein, interpretive naturalist at the park. He has been doing this for 25 years and is quite the fossil guy. “There are more rock layers with fossils than rock layers that are fossil-poor,” Goldstein says of this area. “Kentucky and Indiana have been exposed like this since probably the Permian period. You know, so 200 million years. So there’s been a lot of erosion going on in the last 200 million years. The coalfields of eastern and western Kentucky used to connect.”
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| Alan Goldstein, an interpretive naturalist at the Falls of the Ohio, leads a fossil tour. |
Wearing a park ranger hat and sunglasses, and toting a spray bottle, Goldstein leads me down to the visible rocks of the falls. These are visible even after the spring rains, but some of the best only come out after drought. Along the way, he points out the rocks the park has brought in from surrounding quarries and construction sites to line the steps with even more fossils. At the bottom, Goldstein quickly points out a honeycomb coral, also called a kneecap coral. He sprays it with water, which makes it visually pop. “I like to put a little water on it because it helps to show contrast,” he says.
Goldstein takes me to a fairly bland patch of rock. “Take a picture of this first and then I’ll get it wet,” he says. Spray, spray, spray. Out jumps a jumble of crinoids, looking like Cheerios mixed with broken spaghetti. The Cheerios are simply cross sections of the spaghetti. They’re all the same animals. “Right here — I don’t want to get your phone wet — this is a branching coral,” he says, spraying until a shape the length of my hand appears out of the stone face. “There used to be a crinoid with arms, but it’s been weathering out and may be totally gone now.” He sprays in vain for the fossil.
“Now, are they not a plant?” asks a woman who has hopped onto the tour.
“There’s no fossil plants here,” Goldstein says. “Imagine a starfish with a stem.”
Nearby, he sprays a rock with two fossilized snails — or, rather, the fossilized mud that was inside the snail’s shell. “See that blue thing right at the other end?” he asks, pointing out a slate-colored bit about the size of a thumbnail. “That’s a fishbone. Normally they start out black, but you get some ultraviolet light on them, they turn blue.” There aren’t many fossilized fish, at least not here, in part because fish bloat and float when they die, instead of sinking into the sand of the seafloor.
Nearby, I find a slurry of broken shells that looks exactly like something you might find at the beach today, when the waves make a little valley and deposit enough broken shells to make your feet bleed. Only these are 400 million years old.
And then, Goldstein sprays a trilobite to life, the clear outline of its skeleton now white against the darkened rock. These fossils in the bedrock at the falls are in situ, meaning they have not been moved here but have been here. This whole time. This little trilobite really was crawling right here, 400 million years ago, when it got covered up. Except that right here wasn’t right here exactly.
This place, what we call Louisville, has been many places, many times. The Paleozoic Seas eventually drained. The land shifted. New plants and animals evolved in abundant variety. Eventually, dinosaurs roamed here.
Few places would have been untouched by the presence of the dinosaurs, plesiosaurs and pteranodons. If they’d been sentient, they would have thought this was their world as much as we think it’s our world now. For tens of millions of years, they would have been right. They probably would have had favorite feeding spots, migratory patterns, familiar landmarks. Now, all gone.
The land shifted. The dinosaurs died. The land shifted again. And over time, whatever dinosaur fossils may have once been here eroded and washed away. That’s why there are no dinosaur fossils in Kentucky. Their pages are missing from our geologic book, lost now to time. Sixty million years is plenty for the whole world to change over and over and over again. Even now, Kentucky is moving west one to two centimeters a year toward somewhere else. In 60 million years, Kentucky will again no longer be here; it could be hundreds of miles away. Most of the plants, animals and even the fossils we have known, even some of the hills they were buried in, could be long gone. There are ultimately few survivors of the great crush of geologic time.
Geologic time is like being on a boat out at sea, with no land in sight. You bob up and down. The sea cares not. The sea moves you; you do not move it.
And yet, in our short time, we have altered the world more completely than we realize. Really, it’s humbling just how briefly we have been here. All of us. But, how much we have changed our planet’s future geology? Dumping nitrogen into the soil, carbon into the air, breaking oil and methane out of shale deep down and causing the earth to shake with manmade quakes. In 50 million years, geologists, if there are any, could find fossilized plastic, a signature of our time. And that’s to say nothing of the planet’s biology, where our influence is even more dominant. Corals that have survived for so long — through four mass extinctions — are now under duress as the planet warms at an unprecedented rate.
Perhaps we can’t help it. We are so young, as a species. Fully modern humans have only been around for tens of thousands of years. Like teenagers, our abilities outstrip our wisdom. We may be smart enough to do something, but not smart enough not to do it.
On our way back up from the riverbed, Goldstein and I pass two piles of debris from local quarries, which are the only fossils visitors can take from here. “This helps take the pressure off of people who want to take a fossil, which is a lot of people,” Goldstein says.
Even so, these are relatively slow times for local fossils. The boom was in the earlier days of evolutionary biology. “Most of the research was done in the 19th century,” Goldstein says. Before that, people would have seen fossils for years but not known how they fit into the context of life on Earth. And then, suddenly, they did, the result of a scientific gold rush to discover and name Paleozoic fossils. “That time period has come and gone,” Goldstein says. “All of the people I know who studied these fossils are dead.”
His mentor and the godfather of the local fossil scene was a man named James Conkin, who died just this past December. His wife and writing partner, Barbara Conkin, is still alive but in poor health. Together, with artist Larry Steinrock, they wrote a wonderfully accessible book called Ancient Animals Locked in Louisville’s Rocks. Available at the Louisville Free Public Library, it gives you all the information you need to start finding fossils in Louisville.
Ancient Animals Locked in Louisville’s Rocks, available at the LFPL, will give you all the
information you need to start finding fossils in Louisville.
One of the Conkins’ fans and successors in the art of fossil communication is Michael Popp, who has run the local blog Louisville Fossils and Beyond since 2008. Popp is a computer guy who happens to be interested in fossils, the result of growing up on three acres in Lanesville, Indiana, on the other side of the Knobs from west Louisville. There, not knowing what they were, he would find crinoids and brachiopods in a limestone creek, the same fossils that are so ubiquitous here.
Eight years ago, Popp and a cousin had 20 tons of Waldron shale, from a quarry in Clark County, Indiana, delivered to a field. And then they let the big pile sit. Out in the elements, the soft shale began to crumble away, bringing the harder fossils into the sunlight for the first time in 400 million years. After two years, Popp discovered what he now puts on a blue handkerchief at the Heine Brothers’ on Taylorsville Road. I can only describe it as a creature from another planet. If you told me this was life discovered in the oceans on Jupiter’s moon Europa, I’d believe you. “It’s insane,” Popp says.
He shows me this near-perfect trilobite, its head intact, raised above its body so in profile it makes a curve like a tilde: ~. Usually, you only see the tail of a trilobite. Popp discovered the head and then meticulously screened the shale through a metal grid until he found the tail and could glue the animal back together. This 3.5-inch arthropod now looks as if you could wave a wand and re-animate it. Paleontology is a kind of resurrection.
Falls of the Ohio State Park’s interpretive center was renovated in 2015 to the tune of $6 million. Down a hallway, around a bend, and suddenly — you are at the bottom of an indigo sea. A world I had previously only seen in limestone appears in vibrant color. Hills of coral. Purple tentacled florets popping out of pink honeycomb corals. Crinoids swaying in the current, pink feathers on long orange stalks, bigger than a daisy but smaller than a sunflower. Fat horn corals with orange anemone-like tentacles reaching out of the top. Snails the size of Frisbees. Trilobites hiding in the nooks and scampering across the sand. An ammonite swimming with its many tentacles behind it.
You are living on the bottom of a sea that is no longer here. But with a little imagination, you can breathe life back into the ghosts all around you.
This originally appeared in the August 2018 issue of Louisville Magazine under the headline "Fossils Under Our Feet." To subscribe to Louisville Magazine, click here. To find us on newsstands, click here.
