Weathering and bacterial decay action have modified many of the loose, unconsolidated surface materials into soils. The present soils of Illinois are fertile partly because they have minerals and trace elements (minute amounts of elements such as copper, zinc, manganese) brought in by the glaciers from adjacent parts of the country. The youngest and most fertile soils occur in the northeastern part of the state and along the Illinois and Mississippi River valleys. These young soils are more fertile because the glacial deposits and loess (wind-blown silt) upon which they have developed are younger and fresher. The minerals and trace elements in these deposits have not been dissolved out to the extent that they have in the older glacial deposits and soils in other parts of the state.
Figure 5—Woolly mammoth (after C. R. Knight).
ARE ANIMAL AND PLANT REMAINS FOUND IN THE GLACIAL DEPOSITS OF ILLINOIS?
Scattered mammoth ([fig. 5]) and mastodon remains have been found in glacial deposits at various localities in the state. Peat, which is an accumulation of partially decomposed plant materials, has been found, especially in the northern part of the state. It is marketed as an organic soil conditioner.
MINERAL WEALTH
HOW WEALTHY IS ILLINOIS IN MINERAL PRODUCTION?
In 1963, Illinois mineral production totaled approximately $615,000,000. This placed the state first as a mineral producer in the Upper Mississippi Valley and eighth in the nation.
WHAT MINERAL COMMODITIES ARE PRODUCED IN ILLINOIS?
Coal and petroleum, two of the world’s most important mineral resources, are produced in Illinois. Iron ore, another mineral of extreme importance, is brought into the steel mills of the Chicago and East St. Louis areas from deposits in Minnesota and Missouri. Some ore from foreign countries is also processed in these mills.