Limestone is a most versatile rock. Without it there would be no
portland cement for making concrete roads and buildings, no lime for
plastering and chemical use, no agricultural limestone for farms, and no
crushed limestone for driveways. A wide variety of industries, from
steel making to glass manufacturing, use limestone in one way or
another.
The early settlers of Illinois recognized the value of limestone and
quarried stone blocks and slabs for making foundations, chimneys, and
even houses. For mortar they used a mixture of sand and lime to hold the
blocks together. The lime was made by heating limestone red hot in
simple furnaces or kilns, the ruins of a few of which may still be seen.