Science Grades 6-8: Limestone Information Sheet


What is limestone?

Believe it or not, millions of years ago, most of the
Midwestern United States including Illinois, was
covered by a huge sea! Plants and animals lived in the
sea. As they lived and died, these plants and animals
helped create a substance called calcium carbonate.
The calcium carbonate became part of the rocks which
now lie under much of our soil. One type of rock which
is very common in Illinois is called limestone. The
limestone was formed by the seas long ago. Eventually
the seas receded, leaving behind dry land. The land
was changed again when glaciers, huge sheets of
moving ice, passed over Illinois. The glaciers and the
waters which melted from them carved out valleys and
river beds.

What does limestone have to do with the Canal?

When the Canal was dug between 1836 and 1848,
workers had to cut through limestone in many placed to
form a passageway that would be deep enough for
boats to travel through. People dug, or quarried, the
limestone from the ground. The limestone was used for
building houses and public buildings. Many of these are
still standing. You can identify them by the unevem
surfaces of the stones used to construct the buildings
and by their pretty yellow or soft white color. Limestone
is still quarried and used for construction throughout
the Corridor and along the Canal today.

Refer to Lesson 20 for more information

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