Summer 2003

A quarry lake filled by Big Rock Creek, evidence of a long-ago glacier, a high-quality fen, and a verdant valley lined by high sandy bluffs are found here

Kane County, Illinois

In early summer, as slivers of light sneak through the white oaks to the east, a noisy kingfisher — seeking a meal of fish — skims above the 32-acre quarry lake at Big Rock Forest Preserve.

When Big Rock Creek broke its banks during heavy rains in 1996, it burst through to the abandoned limestone quarry beside it, filling the 65-foot-deep pit and creating habitat for fish, including bluegill, black crappie, largemouth bass, and sunfish. After building an access road, parking lot, and pedestrian bridge, the district opened the site to the public in the spring of 2001.

We stroll northeast on an unpaved road that is sandwiched between Big Rock Creek and the quarry lake. Below us, a ledge of dolomite bedrock parallels the water's edge. Where the trail turns north, slabs of limestone — skeletal remains from the property's previous quarry life — are stacked cairn-like next to the path. Pointed stumps of silver maple and box elder, now weathered silver-gray, hint that beaver once foraged here.

"Big Rock is at the edge of two major divisions in Illinois that are defined by plant communities, glaciation, and topography," says Valerie DePrez, FPDKC nature programs supervisor. "Where the rock shelf is exposed, you can see scratches where the glacier left its mark 10,000 years ago. Fossils in the limestone include creatures from the Ordovician period, such as trilobites and brachiopods."

Farther on, we turn west. Hearing our footfalls, a pheasant hen bursts from her hiding place. Goldfinches bob overhead and add their sweet notes to the summer symphony. Visitors have seen other birds at Big Rock, including osprey, brown creeper, Acadian flycatcher, scarlet tanager, barred owl, tufted titmouse, and wild turkey.

We climb the man-made berm that rises 90 feet above the water's edge. "That's downtown Aurora," says DePrez as she points southeast across the lake. "And just behind us is the district's Deer Valley Golf Course."

Although there's no formal trail, hikers can reach the eastern portion of the preserve by leaving the lakeside road and heading east toward the oak grove along the ridge. Beyond that, the oxbows of Big Rock Creek snake through a verdant valley lined by high, sandy bluffs. Along the creek, massive sycamores tower over ironwood. Trees found in the 80-acre oak-hickory woodland include red, white, bur, and chinquapin oak; bitternut hickory; American and slippery elm; and purple mulberry.

"Other habitats at this diverse site include a high-quality fen and a perched pond [a pond that rests on a shelf, usually clay, above the water table]," notes Drew Ullberg, FPDKC director of planning and development.

Several years ago, the district seeded roughly 20 acres with prairie grasses and forbs. Other native plants at Big Rock include wingstem, swamp thistle, cup plant, spotted Joe Pye weed, sedges, cardinal flower, and Canada wild rye.

Activities at Big Rock include hiking, catch-and-release fishing, and picnicking. Leashed pets are welcome. Swimming is not allowed. A pit toilet is available near the parking lot.

The district has scheduled a nature walk for families from 10 to 11:30 a.m., Saturday, July 12, at the preserve. (No walk if it's raining.) Register at (847) 741-8350, ext. 10.

For more information, see the Big Rock Forest Preserve Web page.

— Ann W. Davis