Since the main ideas of geology are easy to understand and greatly increase one’s enjoyment and appreciation of the world in which we live, the Geological Survey publishes popular and educational booklets designed for the use of Illinois teachers and students. The Survey also distributes a labeled collection of rocks and minerals for class use in Illinois schools. Six geological science field trips are conducted each year throughout various sections of the state for teachers and interested laymen. Members of the Survey staff give illustrated lectures to organized groups about the geology and mineral resources of the state.
Figure 20—Geological Survey offices are located in the Natural Resources Building, Urbana, Illinois.
WHAT IS THE CHARGE FOR THESE SERVICES?
All of the Survey’s publications are distributed free to schools and teachers. Only topographic maps and certain base maps, which are prepared and printed by the U.S. Geological Survey in Washington, are sold at nominal prices.
| Era | General Types of Rocks | |||
|---|---|---|---|---|
| Period or System and Thickness | ||||
| Epoch | ||||
| CENOZOIC “Recent Life” | ||||
| Age of Mammals | ||||
| Quaternary 0-500′ | ||||
| Pleistocene or Glacial Age | ||||
| Recent—alluvium in river valleys | ||||
| Glacial till, glacial outwash, gravel, sand, silt lake deposits of clay and silt, loess and sand dunes; covers nearly all of state except northwest corner and southern tip | ||||
| Tertiary 0-500′ | ||||
| Pliocene | Chert gravel; present in northern, southern, and western Illinois | |||
| Eocene | Mostly micaceous sand with some silt and clay; present only in southern Illinois | |||
| Paleocene | Mostly clay, little sand; present only in southern Illinois | |||
| MESOZOIC “Middle Life” | ||||
| Age of Reptiles | ||||
| Cretaceous 0-300′ | Mostly sand, some thin beds of clay and, locally, gravel; present only in southern Illinois | |||
| PALEOZOIC “Ancient Life” | ||||
| Age of Amphibians and Early Plants | ||||
| Pennsylvanian 0-3,000′ (“Coal Measures”) | Largely shale and sandstone with beds of coal, limestone, and clay | |||
| Mississippian 0-3,500′ | Black and gray shale at base; middle zone of thick limestone that grades to siltstone, chert, and shale; upper zone of interbedded sandstone, shale and limestone | |||
| Age of Fishes | ||||
| Devonian 0-1,500′ | Thick limestone, minor sandstones and shales; largely chert and cherty limestone in southern Illinois | |||
| Age of Invertebrates | ||||
| Silurian 0-1,000′ | Principally dolomite and limestone | |||
| Ordovician 500-2,000′ | Largely dolomite and limestone but contains sandstone, shale, and siltstone formations | |||
| Cambrian 1,500-3,000′ | Chiefly sandstones with some dolomite and shale; exposed only in small areas in north-central Illinois | |||
| ARCHEOZOIC and PROTEROZOIC | ||||
| Igneous and metamorphic rocks; known in Illinois only from deep wells | ||||
Illinois State Geological Survey
Educational Series 9