Coneflower Hill Prairie Moraine
This hill prairie (Cerro Gordo glacial moraine) is part of the Shelbyville moraine and was created by the last glacial period thousands of years ago. Thousands of years have elapsed since the latest ice sheet retreated from this part of the state of Illinois.
The Wisconsin ice sheet moved into Illinois from the northeast and moved southward and westward to a position along a line from Paris through Charleston, Shelbyville, Decatur and Peoria.
The glacial drift deposited at this position of the ice front formed a series of ridges known as a terminal moraine. This deep deposit, built to an elevation of 700 to 750 feet in this vicinity, accumulated as the glacial ice melted and the material carried in and on the ice was dropped. It was in this region that rate of melting equaled the rate of movement of this latest ice sheet and as this continuous flow of ice from the north was checked by melting, tremendous quantities of debris were brought into the region and deposited. The Kaskaskia River then drained away glacial waters which in turn cut the sweeping hills and valleys here and created a vista of peace and beauty unmatched in Illinois. The flat Illinois prairie north of this central Illinois region was the result of the glacier and today has resulted in flat prosperous farmland. Shelbyville marks the southernmost extent of the Wisconsin ice sheet of the Pleistocene “Glacial” Age.
Today the Shelbyville Moraine reaches from Western Indiana to Shelbyville, IL where it turns north at Peoria, IL. The current height of the Shelbyville Moraine varies from 50-100 feet above the surrounding terrain. From the south the land rises somewhat suddenly, then gently peaks and gradually blends into the northern landscape. The view from the north is less noticeable.
The moraine you are standing has an additional characteristic. It is called a hill prairie moraine. A hill prairie is defined as an island-like patch of vegetation occurring on otherwise wooded steep slopes that face south or south-west. In Illinois hill prairies appear intermittently along most of most of the western order of the state formed by the Mississippi River and along the Illinois River from north of Peoria south to its junction with the Mississippi, with a few in east-central Illinois and other scattered localities. Hill prairies occur on the eroded coarse glacial drift, where a river has cut through a terminal moraine. This moraine has also picked up the name Coneflower moraine due to the rare flowers that bloom here. You can find a picture on line if you are interested.
To get credit for this EC, please answer the following questions: (Email your answers to me. Please do not post your answers online in any form)
1. What geologic feature breaches the moraine in the general area of the coordinates given?
2. Using the text above and the provided images, what would be your guess as to the southern reaches of Illinois glaciation?
3. What is the name of the trailhead that starts here? (Not on maps)
4. Estimate the angle of the hillsides. Is one side steeper? Why?
