The Devonian coral reef diorama, based on a coral reef found north of Coralville and on other fossil remains and rock formations from Coralville and Iowa City, depicts the state when it was beneath water 380 million years ago. Providing a sectional view through the reef, this life-sized reconstruction of the sea floor contains the wide variety of marine organisms—snails, sponges, corals, crinoids, trilobites, brachiopods, cephalopods and small fish—that eventually were buried in a lime mud. This deposit later formed a fossiliferous limestone that extends from Iowa City to Waterloo. 

The display also provides an encounter with a larger, less docile inhabitant of the sea floor: the Dunkleosteus, a 20-foot-long, carnivorous armored fish.

To learn more about the Devonian period in Iowa, visit the Devonian Fossil Gorge, located at the Coralville reservoir north of Iowa City.