The gorge was formed in less than a month during the record-breaking Great Flood of 1993.
The limestone bedrock at this site dates back to the Devonian Period, approximately 375 million years ago.
During the Devonian Period, the area that is now Iowa was covered by a warm, shallow sea located south of the equator.
A second significant flood event in 2008 further scoured the site, exposing additional fossils and rock layers.
Geologists identified the bedrock as part of the Little Cedar Formation, specifically the Solon and Rapid Members.
Visitors can see evidence of 'burrowing' creatures that lived in the sediment of the ancient sea floor.
The Devonian Fossil Gorge is an exposed 375-million-year-old limestone sea floor created when the 1993 floodwaters of the Coralville Lake spillway scoured away soil and debris. This geological site provides a rare, easily accessible view of a tropical marine ecosystem preserved in rock. Visitors can walk directly across the exposed rock surfaces, which contain fossils of crinoids, brachiopods, corals, and bryozoans. The gorge offers a unique cross-section of the Devonian period, a time when Iowa was located near the equator. Interpretive signs placed throughout the site explain the geological processes and the types of marine life present in this prehistoric environment. The site is maintained by the U.S. Army Corps of Engineers and remains an active area for geological research.
The elevated observation deck overlooking the expanse of the gorge provides the best panoramic perspective.
Wear footwear with excellent traction, as the limestone rock can be slippery when damp.
Bring sun protection, as the site is wide open with almost no natural shade.
Use the provided educational app or paper guides to identify specific fossil types while walking.
Do not visit during or immediately after heavy rainfall, as the gorge is part of a spillway system and may be subject to closure due to flooding.
The site is typically closed to visitors when water is being released from the Coralville Lake spillway.
Do not collect, remove, or damage any fossils found on-site; all specimens are protected by federal regulations.
