This area of Illinois lacks the granite boulders present in much of the Midwest and has deep ravines and valleys. From this evidence we know it escaped the glaciers of the Pleistocene. The Driftless Division (drift is glacially deposited debris) is characterized by rugged terrain. The area has not only the state’s coldest winters but also its highest point—Charles Mound. The soils are composed of wind-blown loess, disintegrated rock, and flood deposits. At one time most of the landscape was hardwood forest. Although the glaciers missed this area, debris from their melt waters blocked the southeast outlet of the Apple River, causing it to cut a new channel. As the river cut through the masses of limestone, dolomite, and shale to form its new channel, it also formed a rugged and picturesque canyon. This iceless region provided a haven that allowed certain plants and animals to survive the glacial periods. Bird’s-eye primrose is one of these relicts. One hundred years ago bird’s eye primrose tinted the rocks in Apple River Canyon purple with its blooms. Today isolated pockets may still be found.
Interested in exploring this area? Apple River Canyon State Park and Mississippi Palisades State Park are located in this area.