South Flats earthwork site facts for kids

The South Flats earthwork enclosure is an ancient circular mound of earth found in Western Michigan, right next to the Muskegon River. It's one of only a few such earthworks still mostly complete in the area. This special site was first found and dug up by an archaeologist named George Quimby. The earthwork is quite large, about 25 to 30 meters (82 to 98 feet) across, and it sits on a high spot overlooking the river.

Scientists believe that a small group of people, possibly those who spoke the Algonkian language, built this earthwork. They lived in the area between about 1350 and 1650 AD. Even today, archaeologists are still working to fully understand the South Flats site and other similar earthworks found across Michigan.

How the South Flats Site Was Preserved

The land where the South Flats earthwork is located was bought by the South Flats Gun Club in 1929. This happened when they purchased the Muskegon State Game Area in Muskegon County, Michigan. Experts believe that the gun club owning the land actually helped protect the earthwork.

Even though the club made some small changes, like adding hunting blinds, the main structure of the earthwork was not greatly disturbed. The gun club kept control of the land until the 1970s. Then, the Michigan Department of Natural Resources took over the area. They made the land open for people to use for fun activities.

However, this also meant that off-road vehicles and footpaths for hunters started to damage the earthwork. To stop further harm, barriers were put in place to prevent vehicles from driving on the ancient structure.

What the South Flats Area is Like

The South Flats earthwork sits on top of a tall bluff, which is like a high cliff. A small spring cuts through this bluff. From this high spot, you can see the lower floodplain of the Muskegon River. This area is a special "transition zone" where plants and animals from two different regions, Canadian and Carolinian, meet.

Moving around in the lower floodplain can be tricky because of water draining from higher lands through springs and creeks. The earthwork is also located between two important water drainages: Spring Creek to the southwest and the Northeastern Mosquito Creek Drainage.

The plants in this region are mostly oak and pine trees. There are also many cedar swamps. Scientists think that the types of plants here are probably similar to what was growing before people settled the area. The soil at the site is called Rubicon series soil.

Digging Up the Past: Excavations

George Quimby was the first archaeologist to dig at the South Flats earthwork. He did this work in the summer of 1937 as part of an exhibit for the Centennial Organization of Muskegon, Michigan.

Quimby's team dug six different areas, which they called units A to F. They found only a few ancient objects. Based on what he found, Quimby thought the site might have been one of two things:

• A settlement from the Late Woodland time.
• A special ceremonial place from the Middle Woodland time.

Digging Again at South Flats

In the summer of 2006, a team from Grand Valley State University started new archaeological explorations. Their goal was to learn more by building on Quimby's original digs. They wanted to disturb the site as little as possible. They also aimed to research the big question about what these earthwork enclosures were used for in prehistoric times.

The team used a method called shovel tests. They dug small holes along the west end of the 25-meter bluff. They also dug inside and outside the earthen enclosure itself.

What the New Digs Found

After finishing the shovel tests and digging more in Quimby's original six units, the team found something interesting. They discovered much more evidence of ancient human activity inside the earthwork (87% of their tests found cultural material) than outside it (only 37% found material).

Among the items they found were:

• Pieces of pottery (called potsherds)
• Stone tools
• Various animal bones
• Charcoal (burnt wood)

They also uncovered two special areas inside the earthwork that contained some of these ancient remains.

Looking Beneath the Surface: Geophysical Survey

In 2010, two special non-invasive surveys were done. These were called geophysical surveys. The idea was to explore what was hidden underground without digging and damaging the site. These surveys used two technologies: GPR (Ground Penetrating Radar) and magnetometry.

These surveys were very important because it was the first time GPR and magnetometry were used at an earthwork site in Michigan.

What the Surveys Showed

The surveys found some magnetic noise that matched perfectly with the areas Quimby and the GVSU team had already dug. This confirmed where the previous excavations had been.

But they also found several other unusual spots, called "anomalies," that didn't match any previous digging. Four strong magnetic signals, which might be related to the earthwork itself, were confirmed by GPR. These signals were found within 1 meter (about 3 feet) of the surface. This makes these areas very interesting for future digging, as these unusual spots are both on and outside the earthwork.

The information from both GPR and the magnetometer showed that there are more hidden archaeological features. These are located both inside and outside the earthwork. Like the findings from the 2006 digs, these features are not very dense, meaning there aren't a huge number of them.

The newly found possible features of the enclosure include:

• Two features found inside the earthwork.
• One feature along its northern edge.
• Three features just outside its perimeter.

Even though these haven't been dug up yet, the magnetic signals and GPR reflections confirm that these unusual spots exist. They also have similar magnetic patterns to the features found during the 2006 excavation.

A GPR "timeslice" (a special type of image) helped confirm the size and exact location of the earthwork enclosure. This was something that couldn't be clearly identified in earlier digs. The survey showed the earthwork's outer edges are between 35 to 40 meters (115 to 131 feet) across. This makes it one of the smallest earthwork enclosures recorded in Michigan.

What We've Learned So Far

Archaeologists are still trying to find clear answers about what the South Flats earthwork site was used for. There are different ideas about its purpose.

It's common for Michigan earthwork enclosures to have had activities happening inside them. At South Flats, the physical evidence shows that the site was used only a little bit. This doesn't fully prove or disprove any specific uses for this site.

Scientists also looked at the remains of plants. They found no evidence that nuts, seeds, fruits, or domesticated plants were used or eaten. This is unusual because ancient people in Michigan commonly used and relied on these foods. This suggests that using plants was not a main focus at South Flats, and there were no signs of corn (maize) or tobacco.

Here are three main ideas, or hypotheses, about the site's purpose:

• The lack of fish and plant use might mean the site was used during the winter. However, it would have been very hard to move dirt and build the earthwork in an exposed area during winter.
• There might be signs of male activities. This idea is supported by the absence of domesticated plant remains, which were generally grown by prehistoric women.
• The site might have been used for trading between different groups. Other earthwork sites have been found to be possible trading posts or ceremonial places for hunter-gatherers and people who grew crops.

More research is needed to fully understand the South Flats site and what it was used for long ago.