This Month in Archeology

2007 May 14
Koster for the 21st Century

Tucked away in a small side-valley of the Illinois River in southwestern Greene County, the Koster archeological site doesn't look particularly impressive. In fact, like most archeological sites, it doesn't look different from any other place on the landscape at all. Until you look deep enough, that is. At Koster, 'deep enough' is at least 35 feet, and probably more.

Named for the landowners Mary and Teed Koster, the site was excavated between 1969 and 1978 by hundreds of students and professional archeologists. More than two acres of ground were exposed in block-style excavations, the deepest of which reached 35 feet beneath the ground surface. The excavation area was nicknamed the 'big pit' and drew tens of thousands of visitors and tourists each year. Koster was one of the largest archeological excavations of the time, and remains so to this day.

Many people in western Illinois have probably heard of the Koster site. It might surprise you to know that most archeologists throughout the U.S., and even many around the world, have heard of it too. It is famous not just because of the size of the excavations, but because of the well-preserved material that was recovered (hundreds of thousands of cultural and environmental artifacts), and the long time spans involved – the site holds evidence for more than 9,000 years of human occupation.

Located near the base of a tall bluff, the site is above all but the largest of floods but still close to fresh water, fish, and other resources available from the Illinois River. The local uplands of Greene County were covered with a mix of prairies and forests throughout most of prehistoric times, and offered rich plant and animal resources of their own.

Each year small amounts of soil are washed down the bluff and deposited on top of the site, resulting in more than 35 feet of sediment so far. This is the reason for the site's great depth and for the remarkable preservation of its artifacts – as the landscape is covered by the sediment (just fractions of an inch per year on average), archeological material becomes protected from weathering and the natural mixing that occurs in the upper layers of soil. This is why material recovered from Koster includes not just stone tools, but also charcoal, seeds and other plant remains, bone fishhooks, and even a bone flute.

Because of the quality and quantity of artifacts recovered, and because occupations of different time periods are separated by layers of soil (oldest on the bottom, youngest on top), Koster is a window into the past to help us understand how the cultures and technologies of the people who lived there changed through time. Studies from Koster have fundamentally altered our understanding of prehistoric people in North America – how their societies were organized, where and how they acquired food and other material, and what their daily lives were like.

It was at Koster, for example, that archeologists learned how long ago people began forming permanent settlements in North America. Previously we had thought that the earliest settlers were organized in small bands and that there weren't large or substantial settlements until much later times. At Koster there are permanent houses, intricate and non-portable artifacts, and burial grounds dating back to 7,000 years ago. Clearly these people had an elaborate and organized social structure, significant villages, and sophisticated technology, all much earlier than we had realized.

The material recovered from Koster still holds great potential for research. The artifacts were carefully collected and the excavation records document exactly where each one was found. The Center for American Archeology is currently undertaking a research initiative called Koster for the 21st Century, applying new technologies to the material recovered from the site. This project involves researchers with expertise in archeology, the environmental sciences, and computer modeling, working towards a new understanding of the inhabitants of Koster and their changing natural environments.

Modern computer techniques will allow us to create a 3-dimensional "virtual Koster" for display and analysis. We know that the rivers, the vegetation, animals, and other parts of the natural environment changed dramatically over the past 10,000 years. What exactly were these changes in western Illinois, and how did the people at Koster adapt to them? Were some of their strategies for coping with the environment more effective than others? If we can understand environmental adaptations in the past, it may hold clues to how well (or how poorly) we are adapting to our natural environment today.

The 'big pit' at the Koster site is filled in now, and the landscape looks much the same as it did before the excavations began. The lasting impact of those excavations, though, will continue far enough into the future that the original excavations themselves may be of interest to archeologists.

Dr. Gregory Vogel is Director of Research at the Center for American Archeology in Kampsville, Illinois. He may be contacted at: gvogel@caa-archeology.org, or P.O. Box 366, Kampsville, IL, 62053.