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Ice Tree Skirts
A walk along the Illinois and Michigan Canal towpath east of Lemont, Illinois, yields some interesting historic and geologic features. Lemont sits directly on a vast limestone deposit, which, throughout it's history, was quarried for building material. Many of the local buildings, as well as the Chicago Water Tower, were made with stone quarried in Lemont. These abandoned quarries can be seen today, but have filled with water from underground springs. The towpath of the I and M Canal takes you right next to these quarries, now a haven for wildlife and fishermen.
A rare geologic feature is also present along the towpath, a limestone fen. A fen is a wetland (which is really common) but a natural limestone fen is rather rare. Mineral rich waters seep up through the limestone creating shallow ponds that support an interesting variety of plants and wildlife.
The image above was taken as the water in the limestone fen near the "Icebox Quarry" froze and began to drop in level. The ice remains attached to the tree, but since it's floating on the water, it drops with the water and creates interesting rings around things it touched.