One of the places of interest listed for Iowa City is something called the Devonian Fossil Gorge. Since this is an outside area to peruse, and it was another beautiful fall day here, we drove about 13 minutes out of town to check it out.
Life apparently is recorded in layers, and the Devonian layer stretches (from Iowa City) east 60 miles to the Mississippi and north 150 miles to southern Minnesota. It occurred 382 to 389 million years ago. If you had been around at that time, you might have seen the Dunkleosteous, the largest predator of the time, an armor plated fish 33’ long and weighing 4 tons! That to me sounds crazier than sci-fi.
Anyhoo, due to floods in 1993 and again in 2008, Coralville Lake flowed over the emergency spillway and washed away up to 17’ of soil and rock, exposing the Devonian bedrock that became the Devonian Fossil Gorge. The exposed fossils pre-date dinosaurs by almost 200 million years.
We walked through the informative panels and the gorge, trying to wrap our minds around the ancient history of this area.
the lower layers of which are composed of densely packed colonial coral
which are related to modern day anemones and starfish
due to groundwater dissolving parts of the bedrock
which is unfortunately closed indefinitely
Peckish Travels 