Text resources for Guided Practice - Module III-1

The Summer of 1993 will be remembered by many as the Summer of the Great Flood. Heavy rain and a larger than usual snow melt caused the Midwest to see many rivers, including the Mississippi and the Missouri, overflow their banks and destroy many square miles of developed property. But, hard as it may be to believe, the floods did some good, too.

The pictures that follow show the result of uncontrolled flooding on the Iowa River, just north of Interstate 80 in east central Iowa. As water flowed out of control over the spillway, it washed away millions of years of geology, revealing a layer of Devonian-era rock that was rich in fossils. These fossils indicated that this part of the central United States was once covered by a great inland sea, teaming with life.

gorge_entry.JPG - Because the land was part of a flood control dam site, the new resource became part of the Army Corps of Engineers responsibility. It was developed and turned into an outdoor museum. This picture shows the entry to the area, created out of massive pieces of limestone that were quarried not far from the site.

gorge_upstream_walk.JPG - Walkways were created from one end of the gorge to the other, allowing visitors to move safely through the many outcroppings in the former floodplain.

gorge_floodplain.JPG - Although students and the general public are welcome to explore the many fossil outcroppings, no one is allowed to dig them out of the bedrock or remove loose rock from the site.

bluecoral.JPG - It is possible to take something home from the gorge, however. This coral formation is as big as the hood of a car, but students have done rubbings of it to be able to record the many facets of the fossil. Notice that blue crayon has now colored the coral as a result of the work of over-eager geologists.