If you think this stretch of Central Illinois is flat, ask one of those cycling enthusiasts who pedal far out into the countryside. They’ll tell you about a subtly deceiving, gently rolling landscape interspersed with long, broad ridgelines rising as much 100 feet.
Those ridges are called end moraines and were formed during the Wisconsin glacial episode, popularly known as the last Ice Age. As the glaciers began retreating some 20,000 to 25,000 years ago the process was neither smooth nor uniform. When the receding glacier paused (“standstills” could last hundreds of years) ground-up rock and other debris carried conveyer-like by the ice to its margin were deposited, not in an even sheet as usual, but rather in a heap, creating in the process a stutter-step pattern of elongated rises amid a generally smoother landscape.
This mostly slow-motion ballet between the elemental forces of rock and ice left more than 30 end moraines in Illinois, with many tracing a broad arc from northeastern Illinois to the state’s east-central region (these arcs marked the front lobe of a glacier system poking out from the Great Lakes.)
The sweep of the Bloomington moraine, one of six that pass through McLean County, is typical, running as it does from northern Illinois to Peoria and then back east to Bloomington and onward to Saybrook. It’s one of the four largest moraines in all the Prairie State.
For a fine view of this impressive glacial formation, take a drive on U.S. 150 between Downs and LeRoy and look northward. You can’t miss it.
In today’s world of paved roads and drainage tile most of us pay little to no attention to matters involving topography and elevation. But to Native Americans and early settlers, such knowledge was indispensible to travel and the establishment and viability of communities. This was especially true given that the area’s water-retaining black clay left much of the prairie perpetually soggy.
Moraines and their slopes were drier than the wet prairie below, making them natural highways for successive Native American occupants, from Mississippians to the Illinois and finally the Kickapoo. They were also favored for the first roads made by settlers.
A semi-permanent Kickapoo site (now remembered as the Grand Village of the Kickapoo) was situated on the higher-and-drier Bloomington moraine at a site northeast of LeRoy, a natural vantage point in which one could keep an eye on a considerable swath of surrounding territory. And Bloomington itself was located on its namesake moraine for similar reasons.
Before Euro-American settlers arrived in the 1820s, about 10 percent of present-day McLean County was in timber, with much of that along the tops and slopes of moraines.
The county’s second largest forested tract, 14,000-acre Old Town Timber, covered a 12–mile strip of the Bloomington Moraine beginning north of Downs and ending northeast of LeRoy. (In fact, Old Town Timber and Old Town Township are a nod to the aforementioned Grand Village, once better known as the “old town.”)
A century ago LeRoy resident and nature lover Simeon H. West said this forest “contained one of the finest bodies of timber I ever saw in the state.” Yet the hand-drawn whipsaw and steam-powered sawmill made short work of the magnificent old-growth stands. For his part West decried the waste, noting that “the work of the ax-man has been so complete, that even the outlines of the grove, as it was, cannot in many places, now be traced.”
A 20-acre vestige of Old Town Timber’s southeast corner survives as West Park, a 1906 gift from Simeon West to McLean County. And today, not far from old West Park sits the aptly named Moraine View State Recreation Area. This 1,687-acre parkland includes logged-over acreage now reclaimed and a 158-acre lake created from the impoundment of a tributary of Salt Creek.
Still, most morainal land in McLean County is devoted to agriculture, both in row crops and pasture, though a fair amount of private acreage is set aside in timber and used for hunting, recreation and the like. The Bloomington Moraine east of Downs, offering as it does rapid commute times to Bloomington’s east side, is also home to a few sprawling country estates and “McMansions.”
Given their elevated presence on the wide-open prairie some moraines are ideal for a new type of farming — the kind involving the wind. Completed in 2008 and situated (for the most part) on the Bloomington moraine, the Twin Groves Wind Farm and its 240 turbines cover some 22,000 acres of farmland in eastern McLean County.
The Shelbyville moraine south of Atlanta in Logan County marks the furthest advance of the Wisconsin glacial episode. Perceptive motorists driving to Springfield will find the rise and dip of this epochal ridgeline impossible to miss. Beyond it is a landscape forged by an earlier ice age. That means that when one crosses the Shelbyville moraine heading south everything viewed through the windshield is older, geologically speaking, than what is seen in the rearview mirror.