More than 13,000 years ago, a woolly mammoth roamed what is now DuPage County, lumbering across terrain turned frigid by the Ice Age.
Twenty years ago, the prehistoric beast's bones were accidentally unearthed in Blackwell Forest Preserve in Warrenville, a serendipitous discovery that drew 6,000 onlookers to the site over a period of days and focused welcome media attention on the county's natural areas.
"Up to that time, we hadn't had any local event that had brought as much notoriety to the Forest Preserve District," recalled Dan Gooch, a naturalist for the district in 1977 and now its interim executive director. "This thing really caught the public's attention."
To commemorate the 20th anniversary of the discovery of the Blackwell mammoth, an extinct relative of the elephant, the DuPage County Forest Preserve District has scheduled a Mammoth Celebration for June 21. The day kicks off with a hike at Blackwell's McKee Marsh, where district employee Gary Jones unearthed the first bones June 21, 1977, and continues with a program at Fullersburg Woods Environmental Education Center in Oak Brook, where the remains have been on exhibit for the last decade.
More than 800,000 visitors have viewed the skeleton, displayed in a simulated dig site, according to Forest Preserve District attendance figures.
"The exhibit is a big attraction for us," said Fullersburg naturalist Tom Pray. "It's also an important part of our programs for school groups on natural changes in Illinois."
Changes in climate may have done in the Blackwell mammoth, according to Gooch and other naturalists, who speculated that the beast may have become mired in mud as the Ice Age began to recede and the Earth warmed. Lack of evidence of spear marks or arrowheads has led naturalists largely to rule out the possibility that the beast met its demise at the hands of a hunting party.
However the mammoth died, its bones apparently remained buried for thousands of years, until Jones, a heavy-equipment operator for the Forest Preserve District at the time, began excavating blue clay from a Blackwell farm field (now McKee Marsh) for use at a nearby lake.
"I brought up a bucket of clay and noticed something strange sticking out," recalled Jones, now a district landfill inspector. "It turned out to be a thigh bone about 3 feet long.
"Then I saw some rib bones. I knew right away I had hit something strange, so I threw the biggest bone in the back of the pickup truck, took it back to the office and tossed it on the boss' desk."
Naturalists, Gooch recalled, initially were not excited about Jones' find.
"Our first reaction was that it probably was a cow bone or maybe even an elephant bone from a traveling circus in the 1920s," Gooch said. "But when we saw the heavy, reddish-brown bone and looked at the site, we knew that we had something pretty exciting, even if we didn't know quite what it was."
Over the next several days, using shovels and hand trowels, Forest Preserve District workers dug out a 10-foot pit that yielded well-preserved leg bones, ribs, vertabrae, a shoulder blade and an intact pelvis that measured 3 1/2 feet in diameter. Soon, an archeology class from Northern Illinois University arrived to help. Digging continued until early August and unearthed 1,000 bone fragments composing nearly three-quarters of the skeleton. The skull, tusks and front legs were never recovered.
Scientists determined that the animal was most likely a juvenile mammoth, with a shoulder height of 10 or 12 feet; radioactive carbon-14 analysis indicated that the bones had been buried in the clay for 13,130 years.
"Mammoths in our area usually had been figured to be between 8,000 and 10,000 years old, so this find established an additional little piece of natural history for our area," Gooch said.
Though mammoth and mastodon fossils are relatively common in Illinois, the typical find involves isolated bones, according to Michael Parrish, a Northern Illinois University professor who specializes in vertebrate paleontology.
"There seem to have been a lot of mammoths and mastodons in this area, so it is common to find a single bone buried in a river bank," Parrish said. "To find three-quarters of a skeleton is significant and relatively unusual."