Mastodon State Historic Site, located at 1050 Charles J. Becker Drive in Imperial, contains an important archaeological and paleontological site, the Kimmswick Bone Bed, where scientists discovered the first solid evidence of the coexistence of humans and the American mastodon in eastern North America.
At the end of the ice age that occurred from 35,000 to 10,000 years ago, the glaciers to the north were slowly melting as the earth warmed. Animals such as giant ground sloths, peccaries, and hairy, elephantlike mastodons roamed the Midwest. Paleontologists theorize that the area was once swampy and contained mineral springs. Animals that came to the springs may have become trapped in the mud, which helped preserve their bones. Early American Indians also had reached present-day Missouri by at least 12,000 years ago. For a brief period at the end of the Pleistocene epoch, the lives of humans and mastodons intertwined.
The first recorded report of bones of mastodons and other now-extinct animals in the vicinity of the town of Kimmswick was in the early 1800s. Private entrepreneur and St. Louis Museum owner, Albert C. Koch, Ph.D., investigated a report of bones weathering out of the banks along Rock Creek and conducted excavations in 1839. Thinking he had discovered a new animal, he named his find the Missouri Leviathan and exhibited it in the United States and Europe. Richard Owen, a comparative anatomist at the British Museum in London, convinced Koch the skeleton was nothing more than an American mastodon.
At the turn of the century, nationwide interest in the site was revived when amateur St. Louis paleontologist C. W. Beehler excavated several skulls, jaws, teeth, tusks and other fossils. Railroad tours from St. Louis brought many visitors, particularly during the 1904 World’s Fair, to visit Beehler’s wood shack museum near the bone bed. Beehler’s excavations were not well documented so the recovery of stone artifacts in the deposits was not initially accepted as showing the presence of humans during the Pleistocene.
From 1940-1942, excavations by archaeologist Robert McCormick Adams from the St. Louis Academy of Science were sponsored by the Works Progress Administration. He recovered additional fossils but few artifacts. Other private excavations were made subsequent to his work. Unfortunately, many bones and tusks were given away, sold, taken by relic hunters or destroyed by later limestone-quarrying operations.
Public interest in the site was revived in the 1970s during construction of Interstate 55. A movement to save the site from future destruction was organized by the Mastodon Park Committee. Through the efforts of the committee, local legislators, private individuals, corporations and local school children, and with the help of a federal grant, the Missouri Department of Natural Resources was able to purchase the 418 acres containing the bone bed in 1976.
The department sponsored excavations of the bone bed in 1979, 1980, and 1984. In 1979, paleontologist Russell W. Graham of the Illinois State Museum provided the first solid evidence of the coexistence of humans and mastodons, as a stone “Clovis” type projectile point was found in association with mastodon bones. This was the first site in eastern North America where this association was conclusively demonstrated.
The Kimmswick Bone Bed is important in the history of archaeological discovery, as well as a rare example of a stratified ice age Paleo-Indian Clovis culture hunting activity, and one of the oldest known archaeological sites in Missouri (over 10,000 years old). Presently the Clovis culture is the earliest well-documented Native American occupation for North America. Clovis hunters may have contributed to the extinction of many Pleistocene animals. Due to its archaeological and paleontological significance, the Kimmswick Bone Bed was placed on the National Register of Historic Places on April 14, 1987.
Visitors may take the Wildflower Trail that begins next to the museum and leads to the site where the bones and artifacts were found. Until future excavations are sponsored by the Department of Natural Resources, the remnants of the bone bed site remain safely buried for generations to come.