ST. LOUIS, MO, ( – The Mastodon State Historic Site, near Imperial, MO, contains one of the most important archaeological sites in Missouri – the site where archaeologists first discovered a stone weapon with the bones of American mastodons. This was the first solid evidence of the coexistence of humans and mastodons in eastern North America.

The skeleton of an American Mastodon, the largest extinct animal found at the Kimmswick Bone Bed, represents an adult male, 10 feet high and 20 feet long. The skeleton, made of fiberglass molded from original bones currently in the collection of the Illinois State Museum, took about a year and a half to complete.

At the end of the ice age that occurred from 35,000 to 10,000 years ago, the glaciers to the north were moving slowly, melting as the earth warmed, and sending streams of meltwater southward. Animals such as giant ground sloths, peccaries, and hairy, elephant-like mastodons roamed what is now Missouri.

Bones of mastodons and other now-extinct animals were first found in the early 1800s in what is now known as the Kimmswick Bone Bed. Excavations in 1839 and the early 1900s revealed a great many well-preserved bones. The area became known as one of the most extensive Pleistocene bone beds in the country and attracted archaeological and paleontological interest worldwide.

Archaeologists theorize that the area was once swampy and contained mineral springs. Large mammals that came to the spring may have become trapped in the mud, which helped preserve their bones. Other bones may have been washed in by streams. 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 ice age, the lives of humans and mastodons intertwined.

Femur bone and tusk of an American Mastodon on display at the Mastodon State Historic Site.

Bones from more than 60 mastodons reportedly were taken from the pit. Unfortunately, many of the mastodon bones and tusks were given away, sold, taken by relic hunters, or destroyed by later limestone quarrying operations.

In 1970, citizens in the Jefferson County area became concerned about losing this important part of history. A movement to save the site was organized by the Mastodon Park Committee, which was led by four local women. Through the efforts of the committee, local legislators, private individuals and corporations, local schoolchildren, and 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 site became Mastodon State Park, which was renamed Mastodon State Historic Site in 1996.

In 1979, the Illinois State Museum began excavations at the bone bed on behalf of the department. Archaeological history was made at the site when excavators found a large, stone spear point made by hunters of the Clovis period (10,000 – 14,000 years ago) in direct association with mastodon bones. This was the first time archaeologists had found evidence of human weapons interspersed with the bones of these giant prehistoric beasts. This discovery indicated that humans, along with environmental change, may have contributed to the extinction of mastodons.

Archaeological history was made at the site when excavators found a large, stone spear point made by hunters of the Clovis period in direct association with mastodon bones.

Paleo Indians campsites have been discovered in many places throughout the United States. Archaeologists have found related artifacts. Visitors can see a lifescene depicting a Clovis campsite as it may have appeared here at Mastodon State Park 11,000 years ago. The Clovis were from the earliest Paleo Indian period (11,500 – 10,900 years ago). The Indians, who moved about in search of game, are shown performing common tasks associated with the prehistoric culture.

Today, the 425-acre historic site preserves this important archaeological site and provides recreational opportunities. A museum tells the natural and cultural story of the area, while a picnic area and hiking along the Tom Stockwell Wildflower Trail offer chances to explore the land where mastodons and Native American hunters once lived. The museum hours are Monday thru Saturday, 9 a.m. – 4:30 p.m. and Sunday, noon – 4:30 p.m. During winter months, November – March, please call (636) 464-2976 to verify hours.