Devonian Fossil Gorge

The Gift of the Flood

The most incredible thing about this site is how it was discovered. For decades, this area was just a standard road and campground near the Coralville Dam. Then came the Great Flood of 1993. Water surged over the emergency spillway for 28 days straight, acting like a giant pressure washer. It ripped away 15 feet of soil, trees, and road, eventually scouring down to the bedrock. When the water finally receded, it revealed a 375-million-year-old ocean floor. It happened again in 2008, cleaning the rocks off even further. We were literally walking where tropical saltwater once rippled during the "Age of Fishes."

An Ancient Tropical Iowa

It’s wild to stand in the middle of Iowa and realize you are standing on a prehistoric reef. We learned that during the Devonian Period, this entire region was located near the equator and covered by a shallow, warm sea.

As we explored the limestone slabs, we found thousands of fossils embedded right at our feet. It was like a giant, stony "I Spy" game:

• Crinoids: These look like little stacked Cheerios or screws. They are called "sea lilies," but they were actually animals related to starfish.

• Brachiopods: These look like classic seashells (similar to modern clams).

• Hexagonaria Coral: These are colonial corals with a distinct six-sided pattern. Fun fact: these are the same fossils that make up the famous Petoskey Stones in Michigan!

• Horn Corals: These look exactly like their name—solitary, cone-shaped fossils that look a bit like a stone Bugle chip.

Tips for the Trek

We spent about an hour wandering through the gorge, and it was a great way to let the kids explore. A few things we noted for our next visit; Look, Don't take, unlike some other fossil sites, you cannot take anything home here. It’s a protected site, so we stuck to taking "photo trophies" of our finds.  Before you head down, check out the Entry Plaza pillars at the entrance. They are designed to look like the coral fossils you’re about to see and have great info on the Dunkleosteus, a terrifying, 30-foot armored fish that used to rule these waters. The Devonian Fossil Gorge is a powerful reminder of how much history is hidden just beneath our feet. It was a fascinating, "brain-wrinkling" stop that made us look at the Iowa landscape in a whole new way.