I always enjoy stumbling upon boulders like this one. Southern Illinois was glaciated during the Illinoian glacial period, about 310,000 to 128,000 years ago. The Illinoian glacier extended south to the Shawnee Hills, and the change in landscape there is quite dramatic. The more recent Wisconsin glacier occurred between 24,000 and 11,000 years ago, and its southern reach is approximately around Effingham. The soils in Southern Illinois are a mix of Illinoian glacial till, with loess overlying that, mostly from the Wisconsin glacier. There are also big areas of glacial lakebed filled with fine sediments from glacial outwash. Granite boulders like the one above were left here at least 128,000 years ago, and they come in all sizes. Once I found a beautiful quartzite boulder that I would have liked to carry home, but it was at least a couple hundred pounds, and it was about a mile from my truck. Oh Well. I guess if they have been resting comfortably for 128,000 years I should just leave them be.
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