Devonian Fossil Gorge

The Devonian Fossil Gorge near the Coralville Dam in eastern Iowa provides a glimpse of Iowa’s prehistoric past.


Kellie Kramer (Host): In the devastating floods of 1993, flood waters topped the emergency spillway here at the Coralville Dam, sending a torrent of water down the adjacent hillside. Flood waters eroded vast amounts of the landscape, obliterating a road and campground.

Scott Siepker (Host): But out of the devastation, an amazing treasure was discovered, an ancient fossilized sea floor ecosystem frozen in time. Pre-dating the age of the dinosaurs, the Devonian Fossil Gorge is over 375 million years old and is a fascinating glimpse into a piece of Earth's history. 

Pat Witinok (Geologist & US Army Corps of Engineers Volunteer): The Devonian Fossil Gorge is the Grand Canyon of Iowa. And the critters that lived are seen through the fossils. The whole story is here written in the rocks. 

Kramer: Volunteer Pat Witinok is a lifelong learner, educator and lover of geology. For decades, she has been sharing her passion for rocks as an eighth grade science teacher and volunteer for the US Army Corp of Engineers. When the gorge was first revealed, Pat was a student at the University of Iowa, and among the first to explore the unearthed fossils. 

Witinok: When the spillway was topped over, we as geologists knew there was rock under the ground. But the window of the museum that is here was open to all people, and that museum is the Devonian rocks that you see in front of you.

Kramer: Eastern Iowa's outdoor adventurers quickly flocked to the fossil gorge. But its biggest fans are definitely kids.

Kramer: Here, visitors can experience the Devonian Age. Pre-dating the dinosaurs, ancient marine life dominated this period, and their footprint is perfectly preserved in the rock, showcasing much of Iowa's native sea life. 

Witinok: You can see stems from the crinoids, the little cheerios are individual segments. You can see whole brachiopods. So this is limestone, when I hold it in the sun and it glitters, the glittering is calcite, calcium carbonate. 

Kramer: For those who aren't geologists, the gorge entry is lined with illustrated maps and numbered marks explaining the many different aspects of the gorge floor. Undeniably, this piece of geological history is for all to share.   

Witinok: This is a museum, okay. And this is a museum into the past. But yet on top of it, you see things growing, right? So you're in the past by looking at these things and you can go back in time like a time machine, but then you're here also today. And it's like a key to the past.

Excerpt from Iowa Outdoors, Episode 504, Produced by Iowa PBS, 2015.


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