by Jim and Melanie
A sea covered the midwest region of North America about 300 million years ago, eventually forming a deep layer of sandstone in what is now central Iowa. Several past glacial eras carved out diverse landforms across the state. Between 12,000-14,000 years ago, a lobe of ice pushed south from the northern plains and stopped near present day Des Moines. Melting and runoff carved out steep canyons in the sandstone bedrock below, forming what is today Ledges State Park. It is one of Iowa’s favorite parks offering hikes with elevation changes of 150 feet in several places. This topographic map illustrates the rugged terrain. Many people think of Iowa as flat farmland. Most of Iowa isn’t flat.