Where to Look for Fossils
If you plan to collect in a quarry or any other private property, be sure to get permission to enter it. In that way, someone will know where you are in case of accident. In active quarries, there is danger from falling rock during blasting. If the operator of the quarry doesn't know you are there, he cannot warn you when he is going to set off a blast.
Some of the best collecting sites in Illinois are the cliffs and bluffs along our major rivers, the Mississippi, Illinois, Ohio, and Wabash Rivers and their tributaries. At these places, whole fossils are often weathered out and may be picked up easily. Most of Illinois' major rivers have banks of windblown glacial dust, or loess (pronounced "luss"). Shells of air-breathing snails that lived during the Ice Age are common in the loess.
Well-known collecting sites for plant fossils are coal strip mines of Illinois. Perhaps the most famous is the Mazon Creek area near Braidwood in northeastern Illinois, which has supplied beautifully preserved impressions of ferns, tree leaves, and a few insects to museums throughout the world.
This map of the Mazon Creek will help you locate the area of interest. Many strip mines yield fine brachiopods, snails, clams, and cephalopods.
Highway cuts through bedrock commonly expose beds containing fossils, but be careful along road cuts, especially if there is heavy traffic.
Ice Age fossils, such as mammoth and mastodon teeth and tusks, have been found mostly in gravel pits but also in foundation excavations and ditches in all parts of the state.
Actually, you can find fossils almost anywhere, in the gravel or crushed stone of your driveway or in stone walls and foundations. You may see fossils in many places where you cannot collect them, such as counter tops in restaurants, utility marble in public buildings, in stone sidewalks in several of our older cities, or in riprap along the shores of Lake Michigan and our major rivers.