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A Sedimental Journey


Fossil-hunters find remnants of Indiana's oceanic past all over Southern Indiana


devonian_sea
/Photo courtesy of University of Michigan Museum of Natural History

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A spiral of coral reaches up to the sun, visible through the warm, salt currents surrounding it. The soft-bodied, translucent organism inhabits a shallow reef, teeming with small marine creatures that sustain one another. The water is shallow and clear, a balmy 70 degrees year-round.

The coral bears little resemblance to vibrant illustrations found in the pages of science textbooks. Without algae to add vivid pinks and oranges, the coral reef would likely be pale and delicate, almost ghostly in the light from the surface. Bony, primitive fish wind in and out of the spires, and primordial snails make their lethargic way past sedentary mollusks. A few hundred feet above, prehistoric mosses and ferns creep onto the shore, taking root in the scant land that rises above the vast sea.

It seems impossible at first blush, but this tranquil sea once covered what is now Southern Indiana, and the remnants of the creatures that lived there can be found in our rivers and hills and even along our highways. If you dig deep enough in the right places, you’ll find limestone formed around their fossilized shells.

Think back to your middle school lessons about continental drift. Five hundred million years ago, most of the land that we call North America was located in the Southern Hemisphere and remained there for hundreds of millions of years. Corals thrived in tropical seas there, just as they do in the clear, shallow waters of the Indian and Western Pacific oceans today.

Most of Indiana’s fossils we find today date from 300 to 450 million years ago. Corals, flowerlike crinoids and brachiopods reminiscent of mollusks are all relatively common.

Today, the surface of our state is like a hastily made layer cake, with tiers of different fillings piled unevenly atop one another. Fossils from different periods of time become visible in places where older layers are exposed – the banks of the rivers, lakes and creeks or where interstates and highways have cut through the hills.This summer, geologists, naturalists and paleontologists will introduce new generations of fossil-hunters to the mysteries of our marine past and the strange creatures that thrived here.“You talk to anyone, they’ll probably tell you they were that kid who always came in from outside with their pockets full of rocks,” says Tom Odom, a member of the Indiana Paleontology Society. Fossil-finding is not the sole province of professionals, you see. With so many remnants of Indiana’s aquatic past located in and around Southern Indiana, anyone can begin a fossil-finding journey.

IN EARLY SPRING, the Falls of the Ohio State Park is just beginning to see consistently sunny weather. At a comfortable 50 degrees, the visitor center is doing brisk business on a Saturday afternoon, and the deck overlooking the Ohio River is filled with people gazing out over the banks.

Hundreds of people visit the Falls during the summer days, when the weather is clear and sunny. However, most fossil-hunters at the state park today are still picking through the piles of fossil-rich soil and shale delivered from quarries at the end of the parking lot. During the heavy rain and snowmelt of spring, the fossil beds are still covered by the swollen Ohio River. The beds, containing a wealth of marine fossils, are most accessible in August through November, says interpretive naturalist Alan Goldstein.

As the park’s resident paleontology expert, Goldstein spends several afternoons each month leading two-hour talks on the geology of the falls or the Kentuckiana area or identifying fossils. The best exposures, where fossil enthusiasts can see and possibly collect bits of the state’s past, are in Southern Indiana, where sand and gravel wear away to expose fossil-bearing rock, he says.

While park visitors can discover fossils along the river in the warmer months, they can’t collect them. State parks are protected land. But hikers are encouraged to bring cameras and document what they see and to sort through the fossil piles in the parking lot for souvenirs, he says.

Park employees organize annual fossil events – a symposium for serious amateur paleontologists in August with renowned speakers and a “Digging the Past!” day-long festival for beginners in September. For teens, the park offers a three-day career camp in July.

Goldstein and others also train volunteers to lead groups over the edges of the river, where they’ll find themselves walking over the preserved shells of marine creatures embedded in the rock. To make the critters easier to see on these outings, Goldstein or another worker will sometimes take a small scrub brush and water and wash off some of the river-deposited silt for “just a little elbow grease,” as Goldstein calls it. The picnic area also displays large boulders from the river, which provide a taste of what waits on the riverbanks.

“Those boulders are packed with fossils,” Goldstein says, gesturing out the window at the submerged banks. “In the summer, when we take hikers down to the beds, they can’t help stepping on them.”

ALTHOUGH VIRTUALLY ANY CREATURE or plant can become a fossil, most don’t, Goldstein says. During the Devonian period, roughly 390 million years ago, the sea deposited limey sediments that helped preserve the harder corals and marine invertebrates. However, soft-bodied organisms without shells, like worms, weren’t likely to be preserved. Their bodies decayed faster than the minerals could form around them.

Areas that are underwater tend to erode less, and the remains of creatures, large and small, are more likely to be covered in sediment and preserved than they would be on dry land. So even though Indiana’s salt sea existed hundreds of millions of years and several continental movements ago, many of the creatures that lived and died in the aquatic period stuck around in fossil form, buried under rock and dirt.

The exposed layer of limestone that holds the Falls of the Ohio’s marine fossils extends far beyond the banks of the Ohio River. Goldstein says the band of rock runs about a thousand miles to the northeast, underneath Indianapolis and Columbus, Ohio, to Southern Ontario and western New York. The rock that holds these fossils in Indiana is only about 35 feet thick, about three-and-a-half stories.

Fossils are often found in and around present-day bodies of water, Goldstein says. And while creek-stomping isn’t encouraged because of the risk of trespassing on private land, plenty of fossils are found around Lake Monroe and Allen’s Creek near Bloomington.

On a recent, clear afternoon, Lee Suttner brings his educational diagrams depicting geological changes visible around the banks of Lake Monroe. Jim Brophy brings his rock hammer. “Rocks are really history books,” Suttner says. “By looking at rocks from different time periods, we can reconstruct the history of that time period.

“They’re wonderful books,” he continues. “But they’re written in a pretty weird language.”

The two professors of geology at Indiana University are seeking a limestone bioherm, or fossilized coral reef, but their interest lies more in the rock surrounding the remnants of sea creatures than the fossils themselves.

While walking along the edge of the lake, Suttner stops by a cluster of broken rocks that reveal winding tubes of coral. But they focus on the difference between the yellow-brown sandstone containing some of the coral and the duskier siltstone a little farther down the bank.

“The fossils, they’re just things living in these environments,” Suttner says. He prefers the language of the sediment around them.


WHILE SIMPLY SEARCHING for and photographing fossils satisfies many amateur paleontologists, others prefer to build their own collections.

On a cold morning at a road cut alongside Route 1 near St. Leon, Sue Brutkiewicz, 55, is propped at a 45-degree angle against the outcrop, searching for shells among the pebbles. Fifteen or so others, clad in neon safety vests, helmets and heavy boots, are spread out along and above the highway. It’s her first experience hunting for fossils along Indiana’s roads, but Brutkiewicz is a 10-year pro at finding shark teeth along the beaches in Maryland and in searching for ancient ferns in the coal deposits of Ohio.

“You just have to train your eye to look for different things,” she says, peering at the rubble. “I’m not really an Indiana expert.”

Brutkiewicz is a one-year member of the Indiana Society of Paleontology, an organization that plans field trips for fossil-hunters, like the mass carpool to the St. Leon roadcut, or to museums and public collections.

Eyes bright, Brutkiewicz scans the layers of rock for pieces of shell and coral that have been unearthed, occasionally fishing one out with a “that’s nice” or “that’s one to be proud of!” and adding it to her plastic bag. “There’s just so much so much stuff,” she says, peering at the other members hunched over their own tiers hundreds of feet away. “It’s almost like sensory overload – too many things to find.”

Tom Odom, 62, a senior member of the society, pokes around through larger rocks with a metal pole, searching for an elusive trilobite, a small crablike creature.

In many years of trips to this road cut, he’s never found one. But Odom has a few other goals, as well. He’s searching for refined corals and shells now that he’s seasoned enough to be selective. “Everyone has a pile at home of things they thought were pretty good, but don’t seem so good now that they’ve found more,” he says.

Odom searches away from the rest of the club, eschewing the more popular tiers of the road cut in the hopes that he’ll find something great in an overlooked area.

Katherine Armstrong, 61, on the other hand, is suffering the cold for the kids. The fossils she and her husband collect are popular with schoolchildren when the society takes part in educational events.

She, too, is looking for trilobites, the “Holy Grail” of the St. Leon roadcut, as well as cephalopods – curled, tapered shells from squidlike creatures that lived inside, like snails. After about 15 years of hunting in Indiana, Armstrong picks fossils out from the debris almost at a glance. As she pulls herself up the side of the hill, she pauses, then plucks a brachiopod out from under a short ledge, popping it into her bag. “Good eyes and agility helps,” she says.

Armstrong, the society’s current president, believes fostering an interest in paleontology begins with giving kids access to their own, which is why 95 percent of the collecting she and her husband, Bryan, do makes its way into the hands of grade- and middle-schoolers.

“It doesn’t take too long to have everything you need to call it a collection in Indiana,” she says. Other members of the club, like Steve Smith, a retired earth science and geology teacher at Arsenal Technical High School, also have pocketsful of fossils for fairs.

There’s still a healthy air of competition, though. When Jan May approaches Armstrong with a miniscule, pillbug-sized trilobite in hand, Smith huffs. “That’s the tiniest one I think I’ve ever seen,” he says. “I’ll go find his big brother.”


THE SOCIETY AND MEMBERS of the 500 Earth Sciences Club visited fossil collections at the IU Department of Geological Sciences not long ago. They spent more than three hours with research associate Gary Motz, who gave them a tour of the six million fossil specimens in IU’s collection, ranging from microscopic eel teeth to planks of fossilized wood.

Although the groups are active in planning fossil-finding trips in the spring and summer, and museum gatherings during colder months, Odom and some others worry about the future of fossil-hunting. Recently, the group lost its access to many Indiana quarries, which, since they cut deep into the rock layers, often contain plenty of fossils.

Odom admits that concerns for the safety of the groups and the quarries’ investments are understandable, but he thinks adhering to simple safety procedures would eliminate most, if not all, of the risk.

Additionally, the Bureau of Land Management is currently refining the rules for casual fossil collection. Scott Foss, a senior paleontologist with the BLM, says that in 2009, the federal government limited fossil-collecting to "a reasonable amount" on public land. Law enforcement can use their own judgement if they think a person is collecting too much from an area, he says, but there is no hard-and-fast limit, he says.

Nearly a decade later, the BLM is attempting to nail down the previous, vague protections. "The public needs clarity on what these things mean," Foss says. 

Foss is still reviewing 1600 comments from the general public on the first proposed regulations, which won't be redrafted and put into effect within the next six months, but probably will in the next year.

The BLM may alter the proposed regulations slightly, or write entirely new ones based on the feedback they received.

"At the end of the day - and we have not decided yet - if that's the best thing to do, then that's what we'll do," Foss says. "There is no hurry to get it published."

Odom disagrees with the first rules draft, which restricts the amount of fossils more clearly. These rules limit collectors to no more than 25 pounds of specimens in a single day. Recently, the bureau’s website suggested that gatherers will be restricted to 250 pounds per year – an increase from an earlier limit of 100 pounds. Odom says those rules would be fine if the fossils weren’t embedded in rock that must often be removed off-site.

“Particularly if you get to a good site ... 25 pounds a day would go pretty quickly – 100 pounds a year even more so,” Odom says.

And while he agrees that vertebrate fossils like dinosaur bones should be protected and studied, Odom sees marine fossil-collecting differently. “This is a renewable resource, sort of,” he says. “If you leave them alone, they’re just going to erode and disappear anyway.”

THE TWO FOSSIL-COLLECTING PILES behind the interpretive center at Falls of the Ohio are accessible to visitors year round. The park works with Irving Materials to truck down loads of debris from the quarries, Goldstein says. He’s not sure that arrangement will last, though, given the quarries’ insurance concerns, which have limited access for fossil hunters.

As access to the quarries is restricted, road cuts could become more crowded. The goal is always to get to the road cuts in the spring and summer, when snow melt and winter weather have bared new treasure. But exploring a week or two after a large group could mean slimmer pickings.

Goldstein has posted the locations of 13 road cuts on the park website for amateur paleontologists to explore. He chooses broad areas that are unlikely to be cleared out, even if a large group hunts there. Soft sediments, like clay, erode quickly and will expose more fossils in a shorter period of time.

He says “discoveries require a discoverer.” Amateur fossil collectors can usually spend more time collecting than professional paleontologists, who must analyze and teach about their finds. With a little training in how to document where a fossil is found, an amateur can make a discovery that could be named and used for future research. “Paleontology is one of two scientific fields that I know ... where an amateur can make a contribution to the field,” he says. The other is astronomy.

Goldstein leads dozens of hikers, many of them children and students, every day at the Falls. Most of the children are quite young, but he does see elementary or secondary students with strong interests in the field. He says many paleontologists began as fossil-collectors, rooting through silt and rock to get their start.

Back in 1990, Goldstein and a friend made their own amateur discovery – a large, diverse crinoid colony in a Kentucky quarry. The two collected about 900 crinoids over four years and co-authored two papers detailing the nine new species they’d found. “The science of paleontology is built on amateur investigations,” Goldstein says. “That’s the bedrock of paleontology.”

SIDEBAR

Why aren’t there any dinosaur bones in Indiana?

It’s a question naturalist Alan Goldstein gets asked a lot. The answer is that dinosaurs did live in Indiana around 250 million years ago. “We had dinosaurs all over the place,” he says. “Yes, we had T-rexes and hadrosaurids – you name a ‘saurus and they were here,” Goldstein says. But their bones were not often preserved. During the Mesozoic period, most of Indiana was above sea level, which means the bones, and the rocks that encased those fossils, have all eroded away.

“They lived and died on land, which means the bones decomposed,” Goldstein says.

Predators, scavengers, bacteria and the gradual wearing-away of wind, sun and rain would have meant that any carcasses left on land disappeared in the space of a few years.

The closest place to find dinosaurs bones is a field in Bollinger County, Missouri, he says. The odds of Missouri having dinosaur fossils were low as well. But an earthquake dropped a layer of fossil-containing rock below the surface, where it was safe from erosion.

IU research associate Gary Motz has a Sisyphean task ahead of him. Motz is one of two researchers tasked with digitizing the more than 6 million fossils given to the university since 1867. Currently, IU has a digital record of just 0.8 percent of the collection, he says.

Many of these specimens came to IU from fossil-hunters’ personal collections. The fossils must be categorized, identified and then, hopefully, exhaustively photographed and rendered so other researchers with internet access can learn from IU’s rooms and rooms of samples.

It’s a huge, recently started project. Motz acquired a super high-resolution camera and microscope, which he is using to capture IU’s collection of tiny conodont (eel) teeth. With the microscope, Motz divides a single microscope slide into 60 or so sections, fills each one with seven tooth fossils, and takes a photograph detailed enough that a researcher can zoom in and see the deterioration in a single sample.

Motz hopes to photograph and disseminate 30,000 similar pictures at the end of two years.

It’s only one task ahead of him. The research team must also attempt to digitize the fossils that have already been logged manually. He’s also begun to 3D scan the school’s collection of fossils from the Ordovician period.

And with a fossil collection that expands with every Indiana paleontologist’s bequeath, the job is only increasing, he says. “It’s going to take a lifetime of work.”