Louis Agassiz and the Fossil Reefs of Iowa

Abstract

Louis Agassiz's public lectures in population centers on the east coast of the United States are well known, but he also took his ideas to smaller towns in the heart of the continent. These visits by ‘the people's naturalist’ were sometimes touted by local press in these relatively young settlements as a validation of their communities' cultural sophistication. In 1864, Agassiz gave a lecture on fossil Devonian ‘reefs’ at Iowa City, Iowa. According to local tradition, the lecture inspired so much public enthusiasm that a neighboring settlement was subsequently named Coralville. Agassiz tied the Iowa fossils to his own work on modern reefs in Florida, arguing that Devonian expansion of the North American continent had proceeded by coral growth in a manner not unlike the more recent formation of the Florida peninsula. Agassiz's coral work was a centerpiece of his public attacks on the idea of evolution, but it also served to popularize the idea that the Earth had a long history prior to the appearance of humanity.