Coralville: Named for Fossils, Tested by Floods

The town of Coralville sitting just west of Iowa City carries one of the more unusual origin stories in Iowa history, and the story begins not with settlers but with a Swiss-born Harvard zoologist and a pile of fossils.

In the eighteen sixties, Louis Agassiz, one of the most celebrated scientists in America, visited the University of Iowa and gave a lecture about what he called the Coral Reefs of Iowa City. He was describing ancient fossilized coral scattered through the local limestone, evidence that four hundred million years ago this part of the continent sat beneath a shallow tropical sea. When settlers around a new mill on the Iowa River began looking for a name for their community, previously called Clarksville, the coral fossils inspired them. They named it Coralville in eighteen sixty-six.

The town grew around mill power. A dam completed in eighteen forty-three, then rebuilt and expanded, made the Iowa River's energy available for grinding grain and cutting lumber. By the time Coralville incorporated in eighteen seventy-three, it had blacksmiths, saloons, and a dry-goods store. The US Army Corps of Engineers built the Coralville Reservoir upstream in nineteen fifty-eight for flood control.

Then came the floods anyway. In nineteen ninety-three, water poured over the Coralville Dam emergency spillway and carved seventeen feet of soil and sand from the lake bed, exposing Devonian-era bedrock and fossils that had not seen sunlight in hundreds of millions of years. Geologists called it an accidental window into deep time. In two thousand eight, flooding was worse still: over two hundred businesses displaced, more than four hundred households directly impacted, seven million dollars in infrastructure damage.

Coralville rebuilt both times. Today it is home to the University of Iowa Research Park and a lakeside district, a town that keeps rediscovering itself every time the river reminds it who is really in charge.