Finding Fossils Under The Sea (Of Kansas)
Eighty-five million years ago, you wouldn’t have been able to walk around most of the Great Plains; you would have had to swim. A shallow sea stretched from the Yucatan Peninsula to the Arctic Ocean, from the Rocky Mountains to the Appalachians, and it was filled with the ancient relatives of modern fish, turtles, and birds. Some of them might sound familiar: pliosaurs, ichthyosaurs, and the giant mosasaurus. Birds, like the six-foot-long hesperornithes which are said to be the last birds to have true teeth, made their home on and near the water.
We know because their bones are preserved in places in western Kansas laden with soft chalk, which has proved to be one of the richest sources of ancient fossils in all of North America. In this segment from Science Friday’s recent trip to Wichita, Kansas’ Orpheum Theater, Ira talks to two paleontologists, Laura Wilson and Mike Everhart, about the ancient ocean of Kansas, the animals that swam and flew there, and what we’re still learning about how those animals lived and died.
Laura Wilson is an associate professor of geosciences at Fort Hays State University and chief curator at the Sternberg Museum of Natural History in Fort Hays, Kansas.
Mike Everhart is an adjunct curator of paleontology at the Sternberg Museum and the author of Oceans of Kansas: A Natural History of the Western Interior Sea. He’s based in Derby, Kansas.
IRA FLATOW: This is Science Friday. I’m Ira Flatow, coming to you from the Orpheum Theater in Wichita, Kansas.
Yes. Now, Kansas was a different world 85 million years ago. For starters, most of it was underwater. The whole continent was split apart by a shallow sea that stretched from the Gulf of Mexico to the Arctic Ocean, from the Rockies to the Appalachians. And it was full of sea monsters. Sharks, and giant fish, and reptiles 15 meters long swam the sea while pteranodons flew overhead. Plus, six foot long marine birds that still had teeth.
How do we know any of this? When the waters retreated, there remains the bones, the teeth, and even the stomach contents occasionally, stayed put stuck in these soft chalky shells of Western Kansas. In fact, some of the most spectacular fossil finds in North America have come from this state.
Here on stage with me to talk about all the wonders under the Kansas sea, please welcome Laura Wilson, associate professor of geosciences at Fort Hays State University, chief curator of the Sternberg Museum of Natural History in Fort Hays. Welcome.
LAURA WILSON: Thank you.
IRA FLATOW: –and Mike Everhart, acting curator of paleontology at the Sternberg Museum in Fort Hays, and author of Oceans of Kansas, A Natural History of the Western Interior Sea. Welcome. Thank you for coming.
Laura, can you give us an idea how big the sea was?
LAURA WILSON: So from north/south, it stretched from the Arctic Ocean to what’s the Caribbean Sea now. And then east/west, you have to imagine a United States or North America without the Rocky Mountains. So went over to into Utah, and then would stretch into the eastern part of Kansas and into Missouri, where the eastern shoreline was.
IRA FLATOW: And Mike, how did we first discover that Kansas was under water so many eons ago?
MIKE EVERHART: Well actually, the discovery happened during the 1860s and 1870s, more than 100 years ago, when people started finding fossils as the railroad and the settlements took place in Western Kansas.
IRA FLATOW: And so Laura, tell us what lived in the ocean. Describe some of these animals that were there.
LAURA WILSON: So really, very different assemblage in some ways to what we think about with ocean ecosystems today. So you still have fish of all sizes, big teeth, those that are crushing shells. But there are no marine mammals. So when we think of dolphins and whales and seals and sea lions, none of those have evolved yet. So those niches were filled by big marine reptiles.
So we have mosasaurs, and plesiosaurs, and ichthyosaurs. So big lizards essentially, with big teeth and long tails that would be the top predators. We also had some seabirds like we have today. But these are a lot more similar to their dinosaurian ancestors than the ones we might see flying around. And then also, we had the pterosaurs, so the big flying reptiles. They’re not birds, they’re not dinosaurs, but they’re filling a lot of those aerial niches in the ecosystems.
IRA FLATOW: Are there any modern survivors still around of that era?
MIKE EVERHART: No. None of the animals that we’re really interested in today out there have direct descendants. The marine lizards, the mosasaurs and so on were related to modern snakes and monitor lizards, Komodo dragon type stuff. But they are not descendants. And of course, the pteranodons are all gone. Most of the fish species, of course, many lineages of fish are around today. But most of the ones that we collect or see out in the chalk went extinct about the same time as the dinosaurs.
IRA FLATOW: So even though they look like dinosaurs, they have this saur name in them, they were not dinosaurs?
LAURA WILSON: Correct, correct.
IRA FLATOW: Can you explain that a little?
LAURA WILSON: So in a lot of different ways, when we call something a descendent, if we put it on a family comparison, it implies a parent, child, or direct offspring. So these animals would have shared a common ancestor at some point, how you share a grandparent with your cousin. But you’re not a descendant of your cousin.
So they share relatives or a common ancestor with a lot of things that are around today, but it’s not a descendant, an offspring/descendant relationship.
IRA FLATOW: Let’s go to the questions in the audience. Yes, sir?
AUDIENCE: Hi. First off Ira, I would like to thank you on behalf of the Kansas Association of Teachers of Science. We call ourselves KATS.
IRA FLATOW: You’re welcome. Thank you, you’re welcome.
AUDIENCE: So my question is as children, we learned that there are millions and millions of dinosaurs and underwater reptiles. And it makes sense with sharks, because you go into any museum, you can buy shark teeth for like $1. But there’s not millions of mosasaur skulls. So why do we think that there were so many of them back then?
IRA FLATOW: Why were they common? Why do we think they were common?
MIKE EVERHART: Because for one thing, they’re found all over the world. Every continent including Antarctica that has rock deposits of this age includes mosasaurs. Mosasaurs came along late. They were after plesiosaurs, and ichthyosaurs had been around during the Mesozoic for 100 million years. And then these upstart mosasaurs most probably evolved here in North America, but suddenly entered the water. And within 10 to 15 million years, they spread completely around the world.
You have to remember that the planet Earth during the late Cretaceous was a very warm water world. It was about 85% covered with water. There were no icecaps, there were no glaciers, no real winter. So it was the marine animals that basically ran the Earth. The dinosaurs were all kind of limited to 15% of the mass. These guys were everywhere, and they grew bigger and bigger. And they evolved in all kinds of different forms.
So to me, these were really the stars in terms of the creatures that we dig up out of the rocks from the age of dinosaurs.
LAURA WILSON: We can also look to modern ecosystems to some degree as well, when we talk about things like carrying capacity, how many apex predators versus the prey items. And so that alone can give us an idea of what sort of diversity we would expect to find. And looking at less than 1% of living organisms become fossilized, that when we do find fossils, we can kind of extrapolate a little bit off of that about how many we’re not finding just due to different physical and chemical factors.
IRA FLATOW: Where do you find them? I’ll ask both of you, Laura and Mike, where do you go hunting for them? Or do you dig them up?
LAURA WILSON: Well, Mike and I mostly here in Kansas spend our time in Western Kansas, where when it comes to finding fossils, it’s finding the right age rock of the right environment at the surface of the Earth at the right time. And so right now in Western Kansas are the chocks in the shales that have these fantastic creatures in them. And so we can go out, and it’s pretty low tech. You walk around and look at the ground until you find something.
MIKE EVERHART: And that’s really a good description of the process. We’ve got the Badlands in Western Kansas out along the Smoky Hill and the Saline and Solomon Rivers. And it’s just literally square miles of exposed chalk that you walk across. And hopefully, you find teeth, or you find a bone coming out. And that will lead you to a larger specimen. But it’s a lot of just walking and looking.
IRA FLATOW: Let’s go down to the audience here. Yes?
AUDIENCE: What happened to all the water?
IRA FLATOW: What happened to all the water? It’s a great question.
MIKE EVERHART: A very good question, because another thing people don’t understand about Kansas is that we’ve been under water for 500 million years, if you will, 1/2 billion years, all of the mineral resources in this state are sea bottom. Here in Wichita, we’re sitting on about a mile of rock that is all sediments from various seas that have existed here in the past.
But with continental plate movement around this planet, things come together and collide in about 200 million years ago. There was a massive collision on the western coast of North America that pushed up the center of North America, and eventually, at the end of the Cretaceous– 66 million years ago– pushed Kansas above sea level for the last time. And so that’s why we’re sitting up here now about 1,200 foot above the ocean. And we’ll never be an ocean again. But prior to then, we had pretty much always been under water.
IRA FLATOW: We’ll have one final question for you. And I’m sure we have inspired a lot of amateur fossil hunters now.
What do we do if we dig up some fossils? What’s the best thing to do with them? Instead of putting them in your drawer and forgetting about them.
MIKE EVERHART: Well, if you find something that’s big enough that you have to dig it up, don’t do it. Please contact someone who can help you do it right. Fossils are fragile. They’ve been in the ground for 85 million years, in the case of mosasaurs. But once you start taking them out of the ground, they break down into pieces that are useless.
Collecting shark’s teeth or scraps of this, that, and the other, that’s great. But if you happen to come across something that is large and you want to get it out of the ground, get some help. There’s plenty of people at museums that would be glad to give you advice, go out and meet you in the field, whatever. And do it right.
IRA FLATOW: Well, this has been fascinating. Thank you both for taking time to be with us today. Mike Everhart, adjunct curator for Paleontology at the Sternberg Museum, author of Oceans of Kansas, A Natural History of the Western Interior Sea. And Laura Wilson, associate professor of geosciences at Fort Hays State University, chief curator at the Sternberg Museum of Natural History in Fort Hays. Thank you, thank you both again.
LAURA WILSON: Thank you.
IRA FLATOW: And throughout the show, we have a special treat for you, some musical entertainment. Ladies and gentleman, Shane Marler and Nikki Modelmock.
Come on in.
After the break, we’ll talk about the cleanup crews of the natural world, dung beetles and carrion beetles, and the researchers love them.
This is Science Friday from PRI.