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Sand Ridges and Dunes in the Calumet Region
Nature Bulletin No. 709 March 16, 1963
Forest Preserve District of Cook County
Seymour Simon, President
David H. Thompson, Senior Naturalist
SAND RIDGES AND DUNES IN THE CALUMET REGION
Geographers call the area between South Chicago and Michigan City,
Indiana, the Calumet Region because it includes Lake Calumet and the
drainage basins of the Little Calumet and Grand Calumet rivers.
Passengers on airplanes flying to and from Chicago over the southern
end of Lake Michigan can get a better idea of that region and what it
was originally than those who travel on the railroads and highways.
From the air, in spite of tremendous developments since 1905 when the
U. S. Steel corporation purchased 8000 acres of sand dunes and
swamps for its mills and a new city, Gary, you can still see ridge after
ridge paralleling the lake shore as if the country had been furrowed by a
gigantic plow.
The last glacier of the Ice Age, and Lake Chicago -- ancestor of Lake
Michigan -- shaped the main features of Chicagoland. As the ice melted
away the lake's surface was 60 feet higher than at present and it
discharged torrents of water through the DesPlaines river and Sag
valleys. As the glacier found new outlets, two other prominent beach
lines were formed in the Calumet region, each about 20 feet lower than
the previous one.
The famous Indiana dunes were built by winds sweeping down the lake
and creating waves which washed sand and gravel up onto the shore;
and then, after that dried, carrying sand inland until it piled up in ridges
and dunes. One dune, Mt. Tom, is over 200 feet high. As the shore was
extended into the lake, new ridges were created. Just as a snow drift
forms where some object breaks the force of the wind, certain pioneer
plants which are able to gain a foothold and survive on sun-baked sand-
-such as tufts of beach grass and cottonwood seedlings -- play leading
roles in the growth of a dune. With passing years, more and more kinds
of plants occupied each dune in orderly succession until the oldest are
now damp woodlands. In some places there are dozens of those ridges
separated by strips of marsh and swamp.
Because
its far-flung prairies were too wet to farm, the Calumet region
was not settled as early as other parts of Chicagoland but the high dry
beach lines have been main routes for travel around the tip of Lake
Michigan since prehistoric times. Most famous of these is the Great
Sauk Trail from Rock Island, Illinois, across northern Indiana, to
Detroit. Those Indian trails were followed by the pioneers' wagons,
later improved for horse-and-buggy travel, and now are arteries of
roaring traffic.
Industry began with gristmills and sawmills, run by water power, along
the Little Calumet and its tributaries. They ground meal and flour, and
sawed lumber, for homes in early Chicago. Now the steel mills, cement
plants, refineries and a vast complex of factories, served by railroad,
highway and sea-going transportation, have made the Calumet region
one of the greatest industrial areas in the world.
It is a floral melting pot -- a meeting place for plants from many
regions. Few places on this continent have so many species in so small
an area as in the sand dunes of northeastern Indiana. Within a stone's
throw of one spot you can find plants of rich woodlands, of prairies and
swamps, of northern pine woods and tamarack bogs, and plants of the
desert. Some of that has been preserved in the Indiana Dunes State
Park, which serves as a natural botanical garden as well as a
recreational area. A proposed Dunes National Park would preserve still
more of this wonderland.
On a low dune in Shabbona Woods preserve, east of South Holland, is
our Sand Ridge Nature center which will be reopened to the public on
May 1st.
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Update: June 2012
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