West of Batavia on Nelson Lake Road, 270-acre Nelson Lake Marsh Nature Preserve is situated on the lower edge of the moraine. While glacial materials were being deposited and creating ridges, a large lake filled the basin.
``Think of the area as a doughnut,`` Duerr says. ``Around Nelson Lake is a series of moraines, or the outside of the doughnut. When the ice melted, it made the middle of the doughnut--the lake. The lake filled in with dying plant debris, making peat, which is 100 percent organic. The peat accumulates because the plants don`t decompose. The brown soil is some of the richest land in the world.``
Nelson Lake once extended farther southwest. You can even see the old shoreline by walking along the 2 miles of intersecting trails. The lake was also much deeper than its current 12 feet.
Farmers tried to drain the lake in the early 1900s. Buckets were placed on drag lines and thrust into the peat to scoop it up. Because of the land`s low elevation and the many springs, these efforts failed.
This process produced several man-made lakes and precipitated the change from lake to shallow lake to marsh. If you walk slightly off the path, you`ll notice many spots underfoot where the ground is soft, and you may even sink an inch or two because the peat extends 25-30 feet below the surface.
The best time to explore Nelson Lake, Duerr says, is in the summer or fall when the area becomes a kaleidoscope of colors.
There are many rare species of flowers and plants here, Duerr says. Among the greenery living in this wet, boggy environment are fringed gentian, marsh marigolds, goldenrods and wild rice. An alert observer may notice such rare birds as the tawny blade snipe, a sandhill crane or a yellow-headed black bird. Other denizens of the preserve include turtles, salamanders, herrings and deer.
Murray Prairie, which is part of Leroy Oakes Preserve on Dean Street west of Randall Road, is 3 acres of undisturbed prairie. The site is on the same glacial moraine as Nelson Lake, though they are separated by 4 or 5 miles, Duerr says. ``When the glacier retreated, it ran down a hill made of porous limestone--which is under all of the Fox Valley--and left a gravel ridge.``
Because of the dry, black soil`s poor quality, Duerr says, the early farmers didn`t consider it worth farming.
The grass on Murray Prairie grows in clumps, and ``hidden within the blades are some extremely rare plants unique to the Chicago area. And the gravel contains enough nutrients for prairie wildflowers.`` The area does have some shrubbery, such as elderberry and blackberry bushes, on the outskirts of the area where farmers attempted to work the land, he says.
Though Murray Prairie is only 3 acres, it has about 130 varieties of vegetation, such as white prairie clover, azure blue asters, pasqueflowers and native prairie grasses. Inhabitants include the rare jumping mouse, the Franklin`s ground squirrel and the savannah sparrow.
Next to this undisturbed prairie, students from St. Charles High School have re-created the prairie on 3 acres of flat land. In the last decade they have planted native flora that abounded before the area was settled.
On the west side of Minooka Moraine sits the 78-acre Norris Woods. Like Murray Prairie, the quality of this soil was so poor that it couldn`t be farmed. Gravel and sand abounded. But the settlers had cleared the land before they discovered this.
Eventually the trees grew back, and nearly 150 years have passed since the now-towering red and white oaks were last cut for fuel and building materials. In this time the only change to the woods has been the addition of a man-made hiking and biking trail on the east side of the forest that runs along the Fox River, Duerr says.
The area is also rich in flora and fauna. Along the path you might spot a twin leaf, grape leaf fern or blue cohosh and a red-tailed hawk or a great horned owl. You might also see more common animals such as deer, beaver and red fox. Duerr says, ``This is the best example of undisturbed native vegetation. It has rare wildlife, too, particularly the birds.``