Library EventExplore the Devonian Fossil Gorge with ICPL & the Cedar Valley Rocks & Minerals Society

During the Flood of 1993, the Iowa River topped the emergency spillway of the Coralville Reservoir, washing away a road, a campground and almost 17 feet of soil exposing the limestone bedrock beneath and the Devonian age fossils it contains. Fifteen years later, during the Flood of 2008, the spillway was again breached, exposing even more bedrock and expanding the Fossil Gorge to its current size. The exposure allows visitors to walk on rocks that were the floor of a shallow sea that covered the area 375 million years ago, and see fossils of the animals who lived there and their environment. Other features show the results of tectonic forces associated with distant mountain building, groundwater erosion, and the power of the floods that exposed these rocks.

As part of the 2018 Adult Summer Reading Program we’re going to explore the Fossil Gorge. Geologist Ray Anderson and members of the Cedar Valley Rocks and Minerals Society will join us at the Gorge to help us explore and answer our questions. Copies of the Corps of Engineers self-guiding tour brochure will also be available for those who want to explore on their own.

The Devonian Fossil Gorge is located beneath the spillway at the Coralville Reservoir. Take Dubuque Street North 2.6 miles to West Overlook Road. Go East 1.3 miles then follow the road to the right to go below the spillway. We will begin our tour at the marked entrance of the Gorge - just look for the ICPL banner