Rocks are natural combinations of one or more minerals. The three main types of rocks are igneous, metamorphic and sedimentary. Igneous rocks are formed by the cooling of liquid rock on or within the earth. Metamorphic rocks are made as a result fo changes that occur in other rocks from conditions like heat, pressure and chemical reactions. Sedimentary rocks are composed of small pieces of rocks, shells or the remains of living things that build up and are cemented together.
Fossils are evidence of prehistoric life that is preserved in rock.
Minerals, rocks and fossils are fun and interesting to study and collect. An impression of the Tully-Monster was discovered in 1955 by amateur archaeologist Francis J. Tully of Joliet. Since then, more than 100 specimens have been found in Grundy, Kankakee, Will and Fulton counties. Pennsylvanian Myriapod Brett Jurgens Oak Forest, IL Age 10 Jeffrey Cortese South Elgin, IL Age 8 Remember to ask permission before collecting.