An Overview of Prehistoric Archaeology in Minnesota (12,000 BC – AD 1650)
People have lived in Minnesota for over 12,000 years. Modern human populations developed in Africa about 200,000 years ago and began to move north and east out of Africa soon after. They were in southeast Asia by 50,000 years ago, in southeastern Europe and Australia by 40,000 years ago, and in western Europe and northeast Asia by 30,000 years ago. Humans appear to have entered North America by 15,000 years ago.
There are three main theories for routes of initial human migration to North America: on foot across the Bering Land Bridge from Asia via Alaska, by boat from Asia along the northwest coast, and by boat from Europe along the northeast coast.
When people first entered North America many areas would not have been open to human settlement due to the presence of glacial ice and large melt-water lakes. During the maximum extent of the last glaciation about 18,000 years ago, all of Minnesota was covered with ice except the southeastern and southwestern corners of the state. By 14,000 year ago, the warming and drying climate would have uncovered the southern half of Minnesota and the precursors to Glacial Lake Agassiz (e.g., Glacial Lake Benson) were present in southwestern Minnesota. The newly uncovered land was rapidly re-vegetated with spruce forest and tundra grassland, providing food for woodland browsers like mastodon and grassland species like mammoth and caribou.
First Inhabitants – The Paleoindian Tradition
The earliest documented archaeological sites in Minnesota are affiliated with people called Paleoindians whose oldest chipped-stone spearpoints have a characteristic longitudinal flattening on the face called a flute. Fluted points are first associated with a complex called Clovis and later a complex called Folsom. Clovis people are known throughout North America and were long thought to be the first people in the New World.
More recent evidence suggests that the Clovis complex developed in the New World, but they were not the first people in the New World. Pre-Clovis complexes do not appear to have a diagnostic tool type and they had very low population densities so their archaeological remains are scarce and difficult to recognize. No Pre-Clovis sites have been positively identified as of yet in the Midwest. Clovis begins at about 11,500 BC and ends in the western United States about 10,700 BC, but eastern variants survive as late as 10,000 BC.
Clovis peoples lived in an environment very different from today. Large animals such as mammoth, mastodons, and saber-tooth cats were present. The vegetation was dominated by coniferous forests. Huge meltwater lakes covered large areas of western and northern Minnesota feeding outlet rivers swollen with cold water. Glaciers still covered the north and large ice blocks were buried in glacial gravels in the south. Cross-country travel was difficult in many areas as the landscape was unstable due to melting ice and rushing rivers. Vegetal and animal food resources were not as diverse as later times.
Because most of the intact Clovis sites that have been found also feature the bones of mammoths, Clovis peoples are characterized by some as focal big game hunters, but their diet no doubt featured some variety based on local conditions. About 30 Clovis or eastern varieties of early fluted points have been documented as surface finds in Minnesota. The majority of these earliest fluted points have come from central and southeastern Minnesota with very few from the far north and northeast. No intact Clovis archaeological sites have been found in Minnesota.
Clovis in the western United States is replaced by another fluted point complex called Folsom at about 10,800 BC. Folsom lasts until about 9500 BC. Folsom points tend to be smaller than Clovis points and the flute runs almost the entire length and width of the point. Many Folsom sites are associated with kills of large varieties of now-extinct bison. Folsom does not extend much east of the Mississippi River suggesting they were basically grassland hunters. About 20 Folsom points have been recorded in Minnesota as surface finds, most of which have come from western or southern Minnesota. No intact Folsom archeological sites have been found in Minnesota.
Fluted lanceolate spear-points begin to be replaced by unfluted varieties at about 10,000 BC. These unfluted types are lumped together in what is called the Plano Complex or simply Late Paleoindian. Like Clovis and Folsom, all Plano points are lanceolate in form and very well made. There are a number of distinctive Plano point types including Hell Gap, Scottsbluff, Eden, and Agate Basin. Most of these names are from bison kill sites in the Great Plains, but similar points are found in Minnesota. There are over 200 Plano sites known in Minnesota with perhaps 500 total points. As with fluted points, the great majority of these Plano points are surface finds made by avocational artifact collectors. Plano points have been found in all regions of Minnesota except within the basin of the later stages of Lake Agassiz (i.e., the plain of the Red River Valley).
One of the most famous Plano sites was found in a gravel pit at Browns Valley, Minnesota in 1932. William Jensen, a local artifact collector, noticed a human skeleton and beautifully made brown chalcedony spear-points eroding out of the town’s gravel pit wall. By the time University of Minnesota archaeologists arrived on the scene a year later, most of the skeleton and associated artifacts had been removed by the collector. The skeleton became known as Browns Valley Man and the distinctive spear-points as Browns Valley Points. Radiocarbon dates on the bone obtained in the early 1990s suggest the burial dates to about 10,000 years ago, a time when prairie had just begun to invade western Minnesota. Browns Valley Man was probably a bison hunter.
Another important Late Paleoindian Plano site that has been archaeologically investigated in Minnesota is the Bradbury Brook site located south of Onamia. The site was located in 1989 during archaeological survey for the widening of Trunk Highway 169. Salvage excavations took place in 1990 prior to the road construction. The archaeological work uncovered an extensive tool manufacturing station that was utilizing siltstone from a nearby creek bed. A radiocarbon date off a hearth feature suggests the site is 10,000 years old. A broken spear-point from the site resembles Scottsbluff and Alberta types.
Cultural Diversification – The Archaic Period
At about 8000 BC, people in the eastern United States began to exhibit a new way of life that abandoned lanceolate spear-points and featured a more diverse economy. The appearance of what is known as the Archaic Tradition may be delayed at least a thousand years in Minnesota, probably first appearing at about 7000 BC in the southeastern part of the state and even later in the western and northern regions.
Archaic peoples left a great variety of projectile points, most of which were made to fit on atlatl darts rather than thrusting spears. Dart points tend to be smaller and have basal notches or stems to facilitate hafting. Late in the Archaic, people in the Upper Midwest began using cold-hammered copper to make tools. People who used this copper are often referred to as part of the Old Copper Culture. Other Archaic innovations include ground stone tools (e.g., grooved mauls and axes), the domestication of the dog, and the beginnings of horticulture.
The Archaic was a time of increasing temperatures and dryness of which the most dramatic effect was the steady encroachment of prairie grassland from western Minnesota to the east. By Early Archaic times, prairie covered all of southern and western Minnesota and, by the warming, drying peak at about 5000 BC, all of Minnesota was prairie except the northeast. Besides promoting grassland at the expense of forest, the other major environmental effect was the drying-up of shallow lakes and sloughs. All of the lakes in western and southern Minnesota less than 30 feet in depth were probably dry or greatly reduced in size for much of the year during most of the early Archaic. Thus grassland species like bison thrived and wetland and aquatic species like ducks and fish were reduced in density and range.
The Archaic Period in the eastern United States is generally divided into three sub-periods: Early, Middle, and Late. This three-part distinction in Minnesota is not as useful except perhaps in the southeastern corner of the state. In Minnesota, we divide the Archaic by the type of environmental adaption. Thus we have the Prairie Archaic in the west, the Lake Forest Archaic in central and north-central Minnesota, the Shield Archaic in the far northeast, and the Riverine Archaic in the southeast. The Archaic Period is the longest cultural period in Minnesota (7000 – 500 BC), but it is poorly known in much of Minnesota.
The Prairie Archaic
The Prairie Archaic features an adaption to a grassland environment with focal bison hunting lasting for the entire Archaic Period. A bison kill and butchering site located in Itasca State Park is one of the earliest sites and the most famous one from this period. The Itasca Bison site was first excavated by the University of Minnesota in 1937, and again when crews returned from 1963 to 1965. The site yielded the remains of 16 bison of a now-extinct species, as well as small, side-notched dart points. Radiocarbon dates fall between 7600 and 6000 BC. In 1988 another Prairie Archaic bison processing site was found near Granite Falls. This site is dated between 5900 and 5300 BC. It yielded remains of 10 bison as well as side-notched dart points similar to those found at the Itasca site.
By the late Archaic, the climate and vegetation in Minnesota was much like that of the time of Euro-American settlement. Sites in western Minnesota included focal bison kills and small hunting camps in the Red River Valley, such as the Canning site in Norman County. Meanwhile, sites featuring more diverse economies were present in the shallow lake region of southwestern Minnesota such as the Mountain Lake site in Cottonwood County. Another notable difference in the western Minnesota late Prairie Archaic is that copper tools are rare in the southwest, but not uncommon in northwest.
The Lake Forest Archaic
In central Minnesota, the Lake Forest Archaic is not well known with few excavated sites that have clearly defined Archaic horizons. Many of the lakes in this region would not have dried up completely during the early Archaic because many were much deeper than 30 feet and the climate was slightly wetter moving east. More woodland would have survived too, although the early Archaic environment of central and northern Minnesota was still largely prairie. Woodlands increased after the post-glacial thermal maximum about 6,000 years ago. Vegetational diversity led to more animal diversity and thus Lake Forest Archaic economies became broader than the focal bison hunting pattern to the west. Another important factor is the Mississippi River flows through the center of this region, linking people living within the region and also linking the Lake Forest people to people living in regions to the south.
The early Lake Forest Archaic probably closely resembles the Prairie Archaic focal bison hunting pattern, although there may be more variety in the far north and east. There are no well-described, dated sites from this period for the Lake Forest. The best known late Lake Forest site is Petaga Point at Kathio State Park because of its extensive Old Copper component. Most of the copper artifacts come from the collection of pre-park landowner’s collection though, and University of Minnesota excavations there in the mid-1960s produced little copper and little insight into the Late Archaic lifestyle due to stratigraphic mixing.
The Shield Archaic
The Shield Archaic of far northeastern Minnesota is named for the geological region it existed in -- the Canadian Shield -- which features igneous rock outcroppings and shallow soils. Most of the region had boreal forest vegetation at the time of Euro-American settlement, although this forest was more mixed with deciduous species in northeastern Minnesota. This is the environment of the Boundary Waters Canoe Area that is now one of the last true wilderness areas of Minnesota.
The Shield Archaic is mostly known from Canadian archaeological sites. The rich ground-stone tool assemblages of other Archaic traditions are virtually absent in Shield Archaic sites and native copper artifacts are rare. The apparent lack of complexity in Shield Archaic material culture may be due to poor survival of bone and wood artifacts in the acid soils of the coniferous forests. Some researchers believe that Shield Archaic peoples had canoes, snowshoes, toboggans, bark and skin-covered shelters, bark containers, and efficient winter clothing.
In Canada, sites are usually found at the narrows of lakes and rivers where caribou crossings may have existed. The Fowl Lake site on an island just south of the Canadian border is perhaps the best known Shield Archaic site in Minnesota, but most artifacts have come from avocational surface collections.
The Riverine Archaic
The Riverine Archaic is found along the lower Mississippi River and in the attendant deeply-cut river valleys of southeastern Minnesota. The bottomlands of the broad Mississippi River Valley were a rich and varied source of animal and vegetal resources including waterfowl, fish, mussels, and aquatic tubers. The floodplains offered fertile and drought-resistant gardening locations for growing squash and other early cultigens. The uplands had deer, elk, and occasional bison.
Few Archaic sites have been excavated in southeastern Minnesota and no excavated site has exhibited a full Archaic sequence from 7000 to 500 BC. The King Coulee site near Lake City in Wabasha County has yielded the most complete Late Archaic (1500 – 500 BC) information. It was partially excavated by Minnesota Historical Society archaeologists in conjunction with proposed highway construction in 1987. The Late Archaic horizon extended to almost two meters below the current surface and excavation could go no deeper due to the water table. It contained stemmed projectile points, a slate gorget, mussel shells, nuts, and squash seeds. The squash was radiocarbon dated to about 2,500 years ago, the earliest date for a cultigen in Minnesota.
A Time of Innovation – The Woodland Period
About 2,500 years ago people in much of Minnesota began making pottery and constructing burial mounds. In some areas, it is also the beginning of more intensive plant cultivation including early varieties of corn. The bow and arrow appears about half-way through the period, perhaps at about AD 500. With the appearance of the bow and arrow, projectile points get considerably smaller and the points truly become arrowheads. This pattern of technological and religious innovation is called Woodland, because it was first recognized in wooded areas of the Eastern United States.
In the eastern Midwest, the Woodland Period is usually divided into three sub-periods: Early, Middle, and Late. As with the Archaic, this division works well in southeastern Minnesota, but not as well in the rest of the state. Individual Woodland complexes in Minnesota are mostly defined by the types of ceramics present with the ceramics usually named for a geographic feature close to the initial discovery site. Thus in northern Minnesota we have major Woodland complexes called Laurel, Brainerd, and Blackduck. In central Minnesota we have Malmo, St. Croix, Onamia, and Kathio. In southwestern Minnesota we have Fox Lake and Lake Benton. In southeastern Minnesota, we have La Moille, Howard Lake, Sorg, and Effigy Mound.
Burial mounds are present in all of Minnesota except the far northeast. There are no confirmed burial mounds in Lake or Cook counties. There have been over 12,000 mounds recorded in the state, although less than half of these still survive due to intensive cultivation and development over the last 150 years. The three areas with the highest concentrations of mounds are the Red Wing area, the Lake Minnetonka area, and the area around and near Mille Lacs Lake. While mounds were the initial focus of archaeological research, no mounds have been excavated for research purposes since the early 1970s and it is now against the law to excavate a mound without the consent of the Minnesota Indian Affairs Council. About three-quarters of the mounds that were excavated contained burials.
In north-central, northeastern, and east-central Minnesota, wild rice became a very important food during the Woodland Period. Pits were dug to husk the grain and it was then parched in ceramic vessels. The wild rice peoples also hunted a wide variety of animals including deer, obtained fish by various means, and used other vegetal foods. They may have even developed techniques to make maple sugar.
In the Red River Valley, bison were the most important resource, but Woodland people appear to have seasonally moved back and forth between the prairie and the woodlands. In southwestern Minnesota, bison were important and the shallow lakes provided rich aquatic resources including plants, fish, and aquatic mammals such as muskrats. In southeastern Minnesota, Woodland peoples had access to the rich and varied resources of deep and broad river valleys. They also had small gardens in the fertile bottom-lands where they grew squash, beans, and some corn.
Corn and Conflict – The Late Prehistoric
The Woodland Period ends in most of Minnesota at about AD 1000, but it survives virtually unchanged in far northern Minnesota until the French make their appearance in the mid-1600s.
The major cultural influence during this period emanates out from the large prehistoric city of Cahokia across the Mississippi River from modern-day St. Louis. Cahokian influences ascend both the Mississippi and Missouri Rivers in the form of globular ceramics that are tempered with crushed clam shells and an increasing dependence on corn horticulture. Cahokian religious and social ideas also moved throughout the midcontinent.
In southeastern Minnesota, especially around what is now Red Wing, Cahokian influences were the most pronounced with finely-made ceramics closely resembling Cahokia types, large palisaded villages dependent on corn horticulture, and even socio-religious evidences in the form of square earthen mounds that may have been the bases for temples. This cultural manifestation is called Middle Mississippian and the particular expression around Red Wing is referred to as Silvernale. Many of the small burial mounds in the Red Wing area may also be associated with the Middle Mississippian effervescence. Silvernale appears to be a relatively short-lived cultural phenomenon, existing for perhaps only 50 years around AD 1200.
A longer-lived and more broadly distributed cultural complex in the Upper Midwest is called Oneota. Oneota peoples also had some Middle Mississippian influences such as intensive corn horticulture and shell-tempered ceramics, but were more mobile, had broader economies, and did not leave durable non-burial architectural expressions of their socio-religious practices (e.g., temple mounds).
Slightly different Oneota complexes are evident in southeastern Minnesota (called Orr), south-central Minnesota (called Blue Earth), and central Minnesota (called Ogechie). Shell-tempered ceramics featuring globular vessels with high rims are the most distinguishing Oneota trait. Oneota first appears in Minnesota at about AD 1000 and lasts in some areas of the state into the time of French contact. Most Oneota peoples spoke dialects of the Siouan language.
In western Minnesota, Oneota people bumped up against another extensive and long-lasting cultural tradition called Plains Village. The historical expression of this tradition was seen by Lewis and Clark in 1804 as they went up the Missouri River in the Dakotas and encountered the Mandan, Hidatsa, and Arikara. The Plains Village lifeway featured a mixture of corn horticulture and bison hunting. People lived in villages with large earth-lodges and wooden palisades around the outside resembling frontier forts. Ceramics were globular jars that were tempered with crushed rock (grit).
One of these Minnesota Plains Village cultures located just west of Mankato is a concentration of sites called Cambria. Cambria features one major village and a number of smaller satellite villages. Cambria ceramics are grit-tempered, globular jars exhibiting considerable variety. Cambria people grew corn, but also hunted a variety of mammals including deer and bison, fished, collected mussels, and gathered local wild plants. Cambria burials appear to be in mounds. Excavations at the main Cambria site took place in the early 20th century and were done in a surprisingly professional manner.
Another western Minnesota Plains village complex is called Great Oasis, named after the type of site that was excavated by the University of Minnesota in Murray County. The site sat on a large wooded island in what had been one of the largest lakes of southwestern Minnesota. Great Oasis may be one of the earliest Plains Village complexes and is more common in northwestern Iowa and southeastern South Dakota than in southwestern Minnesota. Radiocarbon dates for the Great Oasis complex fall between AD 900 and 1100.
Great Oasis pottery has much less variety than Cambria and has closer affinities to Woodland cultures and Plains Village cultures to the west (e.g., cord-marked vessel bodies). Great Oasis pots are globular, grit-tempered jars with either low, undecorated wedge-shaped rims or high rims decorated with narrow-spaced fine-trailed lines. Stone tools included small, side-notched arrowheads and sandstone arrow-shaft abraders. Like Cambria, bison and corn were an important part of the Great Oasis diet with a wide variety of supplemental foods from both aquatic and upland settings. No Great Oasis burials have been found in Minnesota, but in Iowa, Great Oasis burials are in mounds.
A third Plains Village complex in Minnesota is called Big Stone as it is centered in extreme west-central Minnesota near lakes Big Stone and Traverse. The site that contained the Paleoindian Browns Valley burial also had a Late Prehistoric fortified village affiliated with the Big Stone complex. Big Stone ceramics have some similarities with both Great Oasis and Cambria, along with strong Woodland affinities. Subsistence is assumed to be much like other Plains Villages complexes with corn and bison supplemented with a wide variety of wild food resources.
In central and northern Minnesota, the basic Woodland lifestyle continued into the Late Prehistoric with deer and wild rice being two key resources supplemented with small mammals, waterfowl, fish, and wild vegetal foods. The only evidence for gardening is tobacco at Lake Mille Lacs, although some corn may have been obtained through trade. In central Minnesota, ceramics change from basic Woodland types to a hybrid of Woodland and Oneota traits.
Sandy Lake ceramics are associated with the Psinomani complex. Sandy Lake vessels more closely resemble bowls than the constricted neck jars found in Oneota, Plains Village, and Late Woodland vessels. Temper can be either shell or grit with smooth or cord-marked bodies. There are also Oneota vessels associated with Psinomani, resembling southeastern Minnesota Orr complex vessels. Blends of Oneota and Sandy Lake ceramics traits are sometimes referred to as Ogechie or even Sandyota.
Psinomani people are thought to be the ancestors of today’s Dakota. They were the people living in east central Minnesota when the French entered the region in the mid-1600s. Farther to the north, Blackduck ceramics continued to be used into the Late Prehistoric. Blackduck ceramics probably begin appearing at about AD 700 and may have lasted as late as 1500. Sandy Lake ceramics eventually replace Blackduck in northern Minnesota.