Archive for February, 2012

Plaque atop Monks Mound Showing the Locations of Mounds to the East, Cahokia

One of the distinctive characteristics of Cahokia and its area of strong influence is the prevalence of filed teeth in many human burials. Filing of teeth as a cultural practice was common in Mexico for thousands of years before the Spanish conquest, but further north it is very rare and found mostly at Cahokia and sites in the immediately surrounding area. Gregory Perino published an article in 1967 summarizing the data as of that date on filed teeth at Cahokian sites. He notes that most of the burials with this characteristic were excavated non-professionally and that many of the early excavations were not reported in sufficient detail to know whether tooth-filing was present in the burials they uncovered. Nevertheless, Perino’s article is a useful summary of the evidence at the time.

Interestingly, Perino notes that while most of the reports of filed teeth in North America are from the Cahokia area, there are some scattered early mentions in other regions, including Georgia and the Southwest (!). The Southwestern mention is interesting, as Christy Turner has claimed that some of the remains at Chaco Canyon show filed teeth. None of the other physical anthropologists who have analyzed the relevant remains have noted the same, but that’s not very many people and in general the published physical analyses of the Chaco burials are woefully inadequate. Perino’s reference to a Southwestern example of filed teeth is unclear, but he appears to be citing a previous study of the practice in Illinois which I have not been able to track down.

Setting the comparative question aside, Perino finds three types of tooth filing at Cahokia:

  1. V-shaped notches in the cutting edge of the upper medial and (more rarely) lateral incisors. The number of notches varies from 1 to 4 in the medial incisors and 1 to 2 in the lateral incisors. One example has a single notch in each of the lower medial incisors; this is the only example of filing of any of the lower teeth.
  2. Shallow horizontal grooves along the upper medial incisors above the cutting edge. There can be either one or two grooves, and the grooves can be either parallel to the cutting edge or slightly oblique.
  3. A combination of both of the above types on the same teeth.

Of these, the first category is the most common. The number of notches varies, and they are found more often in the teeth of younger than older individuals, although Perino notes that this is probably because the relevant parts of the teeth have worn away in older individuals. The second and third category are less common, though still somewhat widespread.

Remains of Mounds East of Monks Mound, Cahokia

Perino finds examples of tooth filing both at the Cahokia site itself, particularly in the area of Mounds 19 and 20 east of Monks Mound, and at various locations showing Cahokian influence both to the north in the lower Illinois River valley and to the south in the southern American Bottom. All of the sites he discusses are in the modern state of Illinois. Tooth filing is generally found in only a few individuals in any given burial population, indicating that while it was fairly widespread around Cahokia it was far from universal and generally limited to a small number of people within the society, possibly an elite class. Most of the examples are from men, but there are a few women as well. The chronology of Cahokia was not very well developed at the time, but it appears that the examples of filed teeth mostly date to the height of Cahokia’s power and influence, now dated to approximately AD 1050 to 1200.

Near the end of the paper Perino proposes some suggestions for other areas where similar practices might be identified through further research:

It would not be unreasonable to expect filed teeth to occur in the Tennessee-Cumberland area, in southeast Missouri, and in earlier parts of the Caddoan area, especially at Spiro. Relationships in these areas are noted through trade objects and a  similarity in their religious practices.

These are certainly among the areas showing extensive contact with the American Bottom during the Mississippian period, but they are not the only such areas. What additionally distinguishes them is that they all lie south of Cahokia, and it seems likely that what Perino has in mind here (although he doesn’t say so explicitly) is that these areas may have served as conduits for the transmittal of tooth-filing from Mexico to Cahokia. Be that as it may, as far as I know this practice has not in fact been identified in any of these other areas, which would cast doubt on the idea that it diffused from Mexico to Cahokia, unless Cahokian elites actually went directly there themselves and brought back this (and other?) ideas.

The question of the extent of Mesoamerican influence on Mississippian culture has been hotly debated over the years; the current trend seems to be to downplay the possibility of direct connections and focus on in situ explanations of the Mississippian Emergence. I’m not sure what to think about this, myself. There are a lot of things about Mississippian societies that certainly look very Mesoamerican, at least at first glance, but it’s not clear how many of these are specifically Mesoamerican developments rather than things that typically happen at a certain level of sociopolitical complexity cross-culturally and that are therefore likely to have emerged in the Mississippian context from underlying trends the same way they did in Mexico much earlier. Tooth-filing seems a lot more specific than that sort of thing, though, and I can see it as a strong piece of evidence for direct influence, but the lack of it in the intervening area (if that does in fact turn out to be the case) would be problematic for that interpretation. It seems like a weird thing to do, but it’s not totally unique to Mexico in a global context, so it’s certainly possible that the Cahokians came up with it on their own as well.
Perino, G. (1967). Additional Discoveries of Filed Teeth in the Cahokia Area American Antiquity, 32 (4) DOI: 10.2307/2694083


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View of Monks Mound from the East, Cahokia

Monks Mound is both the largest mound at Cahokia and the largest at any Mississippian site, by a huge margin. It’s 100 feet high and about 1,000 by 800 feet at the base, covering more than 18 acres. Its mass is five times that of the second-largest Mississippian mound (Mound A at the Etowah site in Georgia). The thing is just gigantic, and it has long been of intense interest to archaeologists. Back in the nineteenth century there was considerable debate over whether it was an artificial mound at all rather than some sort of unusual natural formation, and even into the early twentieth century there was some discussion of whether it might have been a natural rise of some sort that was built up artificially. Those debates had largely been settled by the 1960s, with increasing evidence that it was in fact an artificial construction like the smaller mounds surrounding and forming the core of the Cahokia site around the Grand Plaza. There still remained a dearth of detailed information on the composition of the mound, however, and after some excavation of various small parts of the mound in the early 1960s the archaeologists working at Cahokia came up with the idea of doing some core drilling to get a more general sense of its composition. They reported their results in a paper published in 1968.

After reviewing the techniques available to them, the researchers decided to go with the heaviest equipment they could find, a truck-mounted rig used to take soil samples for highway and building construction. This rig worked by ramming a three-inch diameter tube down at two-foot increments, after each of which the core sample would be extracted and a new tube attached to take the next two-foot sample. This worked pretty well, although some of the tubes broke loose, broke, or were otherwise lost in the course of drilling. The clay soils of the American Bottom are notoriously tough on equipment, so it’s probably a good thing they chose the most heavy-duty rig they could. They found that the core samples were somewhat compacted from the pressure of the drilling, but this didn’t end up being a major problem for interpreting them.

View of Monks Mound from the South, Cahokia

To check on the accuracy of interpretations derived from the core sampling, a small area adjacent to one of the sampling holes was excavated to get a better look at the stratigraphy. This digging generally confirmed the interpretation of the cores, especially the interpretation of thin bands of limonite, which often forms on exposed surfaces in this area, as indicating discrete construction stages of the mound. The coring and excavation also resulted in the submission of a few pieces of wood for radiocarbon dating to give a sense for the absolute chronology of mound construction. Since this was early in the history of radiocarbon dating, the standard deviations on the resulting dates are so large as to make the results of limited usefulness in delimiting substages within the Mississippian period, but they do show the general period when the mound was most likely under construction to be between AD 800 and 1300, which matches the dating of the Emergent Mississippian and Mississippian periods at Cahokia.

Probably the most important result of this research was the discovery that two of the major construction stages, including the earliest, consisted of massive deposits of black clay which likely came from topsoil deposits in various areas around the mound. The later paper I discussed earlier suggested that some of this clay may have come from the upper layers of the area to the south that would later be filled in to become the Grand Plaza, while the authors of the original paper suggested that some of it may have come from the area to the north along Cahokia Creek. It probably took a hell of a lot of clay to build these layers, so both could easily be right.

Closeup of Monks Mound Sign, Cahokia

Another interesting proposal from the authors of the coring paper is that the other mounds at Cahokia may have postdated Monks Mound. This is based on the fact that the handful of radiocarbon dates from excavations beneath other mounds that had been obtained as of that time were uniformly later (though not necessarily very much so) than the dates obtained from the coring and excavation at Monks Mound. This idea is supported by the fact that some of the other mounds are clearly aligned with Monks Mound. There has been a lot of excavation and reanalysis of older materials since the 1960s, of course, so I’m not sure if this pattern still holds up.

Monks Mound is both so huge and so important that this sort of broad-scale coring, like the conductivity survey done later in the Grand Plaza, is a reasonable way to quickly get a general sense of patterns that would take much longer to uncover via excavation, which might not even be possible to do on account of preservation concerns. This is therefore a pretty important paper. Even though it doesn’t reveal a whole lot of detail about the construction stages of Monks Mound, it’s unlikely that we’ll get much more detail than this without a seriously huge effort.
Reed, N., Bennett, J., & Porter, J. (1968). Solid Core Drilling of Monks Mound: Technique and Findings American Antiquity, 33 (2) DOI: 10.2307/278515

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Sign Explaining the Grand Plaza at Cahokia

Mississippian societies are known for their mounds, but there’s more to them than that even if you just look at community layout at the largest centers. One of the most distinctive characteristics of Mississippian mound centers is that the mounds at the biggest centers are typically grouped very formally around a central plaza. Historic records of the Mississippian societies in the Southeast that survived into the sixteenth and seventeenth centuries give some sense of the uses of these plazas, which as you might expect seem to have centered on communal ritual, feasting, games, and other events that brought people together and solidified the authority of the elites who lived on the mounds and governed the commoners. Archaeologists have been slow to give plazas the same level of attention they’ve given mounds for a long time, however. There’s long been a tendency to view them as simply empty spaces devoid of interest compared to the impressive mounds that surround them.

That has started to change over the past twenty years or so, however. One of the early efforts in this direction was a field school at the biggest and most spectacular Mississippian site, Cahokia, in 1989. The results of this research were reported in an article published in 1993, and they reveal that there’s more to Cahokia’s Grand Plaza than meets the eye.

Grand Plaza from Monk's Mound, Cahokia

The American Bottom, where Cahokia is located, is characterized by a relatively flat but gently rolling terrain resulting from many years of the Mississippi River winding its way across the floodplain, creating a wide variety of sand ridges interspersed with lower swales filled with alluvial silt and clay. Given this context, the flatness of the Grand Plaza calls out for some sort of explanation. One possibility is that this is an area where natural deposition of sediment happens to have filled in the swales and covered over the ridges, creating a particularly flat area that the Cahokians took advantage of as a natural plaza site by building mounds around it. Other parts of the Cahokia site that have been excavated appear to have been built on similar natural flats. The other option is that the Cahokians themselves took an area that was dominated by the usual ridge and swale topography and flattened it out by cutting down the ridges and filling in the swales to create an artificially flat plaza. If this were the case it would obviously have important implications for the amount of labor that went into the building of Cahokia, which in turn would be an important factor in understanding the nature of the site and of its influence in other areas.

To investigate this question the researchers started with an electromagnetic conductivity survey of the western portion of the Grand Plaza. Since sand tends to have a lower conductivity than silts and clays, sand ridges should show up in a survey like this as areas of lower conductivity compared to swales. This sort of survey should also pick up underground borrow pits (where material was dug for use in mounds and other construction) that were later filled in, provided the later fill was different in conductivity from the surrounding soil. The survey was followed by core sampling to confirm the results, then by limited excavation of a few blocks in the plaza to get a closer look at the stratigraphy of areas that came up with interesting survey results.

The Grand Plaza and Monks Mound, Cahokia

The conductivity survey found that there was indeed a subterranean sand ridge under part of the plaza, with apparent swales on either side of it. Some apparent borrow pits also showed up. The coring confirmed these results, and five excavation blocks were dug: two on the ridge, two in an adjacent swale, and one in a possible borrow pit.

The excavation results showed pretty clearly that the final flat condition of the plaza was indeed the result of human action rather than natural deposition. There was a very sharp delineation between the underlying natural deposits of both the ridge and the swale and the overlying fill, which contained varying amounts of artifacts and did not look anything like natural alluviation. This was also the case for the borrow pit, where the fill was indeed quite different from the surrounding material and clearly secondary.

From the artifacts found in the fill, it appears that the leveling of the plaza occurred around the time of the transition from the Emergent Mississippian to the Mississippian period, which current dating places around AD 1050. Interestingly, it appears that the leveling was actually a secondary activity after the area had been pretty thoroughly dug over for fill, perhaps to build the early mounds at the site. This means that this may in fact have originally been a naturally flat area (although there’s really no way to be sure) but that the upper layers of soil were stripped away for mound construction early on, only to have the resulting pits and scars covered up later by fill that created the final plaza surface. The authors propose a tentative scenario in which early mound construction during the Emergent Mississippian period took fill from this area, which was at the time away from the main area of occupation along Cahokia Creek to the north, and it was only later, when Cahokia began to really hit its stride, that plans changed and this area was refilled to become the Grand Plaza. Whether this was the case or not, it’s very clear from this study that the history of the Grand Plaza is a lot more complicated than it looks at first site.
Holley, G., Dalan, R., & Smith, P. (1993). Investigations in the Cahokia Site Grand Plaza American Antiquity, 58 (2) DOI: 10.2307/281972

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Garden at Chucalissa Mounds, Memphis, Tennessee

One of the main ways Mississippian societies differed from earlier societies in eastern North America was in their much heavier reliance on maize agriculture for subsistence. There had been agriculture, and even maize, before in the east, but the Mississippians farmed much more intensively and used maize in particular much more heavily than people had before. The high productivity of maize agriculture presumably led to the increased population and more elaborate societies characteristic of the Mississippians, and also would have provided a dependable basis for the incipient urbanism seen in the biggest Mississippian centers like Cahokia. While maize had been introduced (ultimately from Mesoamerica and probably via the Southwest, although the details remain murky) to parts of the Eastern Woodlands hundreds of years before the rise of Mississippian societies after AD 900, it was only with the so-called “Mississippian Emergence” that it became a staple crop. The amount of maize typically found at archaeological sites in the east skyrockets after the Emergence, and intensive use of this crop seems to be a fundamental characteristic of the Mississippian lifeway.

Most of this has been known for a long time, based on the amount of maize found in Mississippian sites, but actually identifying and studying the fields where maize and other crops were grown had to wait until the incorporation of aerial photography into Midwestern archaeology in the 1960s. An important early contribution to knowledge of these issues is a paper published by Melvin Fowler in 1969. Fowler reports on work done by Southern Illinois University over the preceding few years at Mississippian sites in that incorporated aerial photography. He focuses on two sites specifically: the Lunsford-Pulcher site, a secondary mound center about 7 miles south of Cahokia, and the Texas site, a smaller farmstead on the Kaskaskia River about 50 miles east of Cahokia.

In both cases, aerial photography indicated the presence of parallel ridges that were not obvious on the ground in the proximity of the main architectural components of the sites. Surface collection of artifacts indicated a particular association between these ridges and fragments of the flaked-stone hoes that are very common at Mississippian sites, strengthening the hypothesis that the ridges indicated fields. Excavation further confirmed the hypothesis, revealing that the ridges consisted of dark topsoil piled up and revealing the lighter subsoil between the ridges. The narrowness of the ridges further indicated that they were definitely prehistoric and not the result of historic plowing. Fowler also refers to evidence from excavations in the 1930s at Ocmulgee National Monument, a major Mississippian center in Georgia, that revealed very similar ridges beneath at least one mound. This indicates that rather than an idiosyncratic practice in southern Illinois these ridges were a widespread Mississippian trait, apparently connected to hoe agriculture. He also refers to historical accounts from the nineteenth century indicating that similar ridged fields covered vast areas of Wisconsin and Michigan before white settlement.

Gardening Sign, Chucalissa Mounds, Memphis, Tennessee

The exact reason for the ridges was unclear to Fowler, and he offered just a few tentative ideas. It could have been a development stemming from the adoption of hoes, which would have been more effective than the digging sticks used previously and may have made it easier to pile up good soil for planting. The linear ridges of Mississippian agriculture may have been more efficient than the small hills used previously and associated with the use of the digging stick rather than the hoe. They may also have contributed to a more effective distribution of water to the plants; irrigation would not have been necessary in this wet climate, but a more efficient use of the copious rainfall may have been beneficial. It is also possible that the ridging allowed the use of low-lying land along rivers that would otherwise have been too swampy for planting. The two Illinois sites are certainly in locations where this would likely have been a factor, although Fowler notes that this is not the case for all the other reported areas with ridged fields.

Overall, this is an interesting study pointing out the advantages of aerial photography for identifying subtle archaeological features that may not be apparent on the ground. I am reminded especially of the Chaco road system, which was similarly identified via aerial photography a few years later. Also, and this has nothing to do with this particular article, I was interested to see the following notice in a box at the end of the last page:


A formal review procedure for all papers submitted to American Antiquity is being initiated. Papers will be evaluated by two referees; authors will receive copies of referee comments (unidentified as to source). Beginning immediately, THREE COPIES of all articles and submissions to Facts and Comments must be submitted. Contributions will not be considered for publication unless submitted in triplicate. Address inquiries to the editor-elect, EDWIN N. WILMSEN, Museum of Anthropology, Universitv of Michigan, Ann Arbor, Michigan, 48104.

Peer review was slow to catch on in archaeology, it seems.

Fowler, M. (1969). Middle Mississippian Agricultural Fields American Antiquity, 34 (4) DOI: 10.2307/277733

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Illinois Welcome Sign

The name “Cahokia” comes from one of the constituent tribes of the Illinois Confederacy, a group of several semi-autonomous “tribes” or “villages” that occupied much of what is now the state of Illinois and parts of some of the surrounding states in the seventeenth and eighteenth centuries. Staunch allies of the French throughout most of the colonial period, the Illinois were among the hardest-hit by the various forces buffeting Native American groups in the wake of European contact, and they ended up suffering one of the most dramatic demographic collapses of the tribes we have substantial information on. Emily Blasingham, who did a detailed ethnohistoric study of Illinois population decline in the 1950s, concluded that the total population of the Confederacy at the time of French contact in the 1670s was around 10,000, which by 1800 had dwindled all the way to a mere 500 people. The descendants of the remaining Illinois ended up in northeastern Oklahoma, where they are now known as the Peoria (originally the name of one of the constituent tribes of the Confederacy along with the Cahokia, Kaskaskia, and others).

Most of the member tribes of the Confederacy, including the Cahokia and Peoria, spoke dialects of the Miami-Illinois language, part of the widespread Algonquian language family. One possible exception is the poorly known Michigamea, who joined the Confederacy in the early eighteenth century and had apparently lived before that somewhere further down the Mississippi River. While it has generally been assumed that the Michigamea also spoke Miami-Illinois, there is some evidence that they may actually have spoken a different language, possibly belonging to the Siouan family, before they joined the Confederacy. Be that as it may, the Illinois Confederacy as a whole was clearly primarily a group of tribes who lived near each other in the seventeenth century and spoke the same language.

Cahokia Courthouse, Cahokia, Illinois

The various Illinois groups moved around quite a lot during the colonial period in response to various threats and opportunities, but they had two main focuses of settlement: the upper Illinois River valley, especially around Starved Rock and Peoria Lake, and the American Bottom, along the Mississippi River between the mouths of the Illinois and Kaskaskia Rivers. The Cahokias consistently lived in the American Bottom for most of their recorded history, and gave their name to both the French settlement of Cahokia, which still exists as the town of Cahokia, Illinois, with its famous courthouse, and the nearby Cahokia Mounds.

The question of who built the Cahokia Mounds, and even if they were artificial at all, was hotly debated in the early history of American archaeology. Even after the early period of wild speculation in the nineteenth century had given way to a more systematic, realistic approach in the early twentieth, the answer remained unclear. In 1944 Donald Wray and Hale Smith, two archaeologists from the University of Chicago, proposed an answer with at least a surface degree of elegance and plausibility, namely, that Cahokia and other Mississippian sites in the region were the work of the Illinois Confederacy.

Southwest Corner of Monks Mound, Cahokia Mounds, Collinsville, Illinois

Wray and Smith had two main lines of evidence for this proposal: distributional and chronological. They noted, first, that the remains of what was then called the “Middle Mississippi Culture” corresponded pretty closely to the areas known to have been occupied by the Illinois in colonial times. Recall that the main areas of Illinois settlement were in the American Bottom and along the upper Illinois River, both areas that do indeed have substantial Mississippian remains. They also note that the general uniformity of Mississippian material culture suggests substantial social and political ties among the groups living in various parts of the region, such as would have been the case with a Confederacy such as that of the Illinois. Note that they don’t point to any specific material culture similarities between Mississippian sites and known Illinois sites, presumably because none of the latter were known at the time.

Their chronological argument takes a somewhat different tack. They note that other archaeologists had recently proposed that Mississippian societies dated to the sixteenth and seventeenth centuries, based on the lack of mention of some of the major mound sites by the early European explorers. Since the only occupants of the Mississippian parts of Illinois during this period are known to have been the Illinois groups, it follows that they must have been the Mississippians. They also go into some detail about certain sites showing contact between the Mississippians and the Oneota culture found primarily further north and tentatively identified with the speakers of Chiwere Siouan languages (i.e., Ioway, Oto, and Missouria). Since many Oneota sites have European trade goods and therefore clearly date to the contact period, Wray and Smith conclude that sites such as some in northern Illinois showing both Oneota and Mississippian traits support their chronological reconstruction. They also note the contacts between the American Bottom Mississippian sites and the southeast Missouri/northeast Arkansas area occupied historically by the Siouan-speaking Quapaw and connect this on somewhat shaky grounds to the Oneota as well.

Interpretive Sign at Southwest Corner of Monks Mound, Cahokia Mounds

We now know that this is all wrong, of course. Wray and Smith were working at a time when there was no way to get absolute dates for archaeological sites in the Midwest, and their chronological assumptions turned out to be totally unfounded when radiocarbon dating was invented a few years later and it turned out that the Mississippian sites were much older than the Illinois Confederacy and that in between there was a period when the American Bottom was part of the “Vacant Quarter” abandoned by the Mississippians. While it’s not impossible that some of the ancestors of the people who would later become the Illinois were involved in some Mississippian societies, there is no particular reason to connect them to the American Bottom specifically, and there is certainly lots of evidence indicating that the Illinois Confederacy itself came many centuries after the Mississippian phenomenon and had no direct connection to it.

While it’s easy to criticize ideas like this in hindsight, with the benefit of more and better information accumulated over several decades, it’s important to note that Wray and Smith’s ideas were actually challenged quite vigorously at the time by Waldo Wedel of the Smithsonian, who published a comment the following year aggressively pointing out the weakness of their assumptions and the dubiousness of their conclusions. Wedel points out that there are no known European trade goods associated with Mississippian sites in Illinois and that there is no evidence at all linking the Mississippian sites to the Illinois Confederacy despite their similar geographical distributions. He also challenges the idea that Mississippian societies in general are post-contact, and points out that while it was a possible interpretation of the evidence available at the time it was definitely not the only one and was lacking in actual supporting evidence. Further, he points out that while some Oneota sites are definitely post-contact, not all of the known sites had produced European trade goods, and it was not at all clear that all Oneota sites were historic rather than prehistoric. Also, he notes that the Quapaw stuff doesn’t make any sense and seems to be predicated on the assumption that since the Quapaw spoke a Siouan language and Oneota was thought to represent Siouan speakers the Quapaw could somehow be associated with Oneota despite the lack of any known Oneota sites in the Quapaw area. Wedel takes great pains to note that he is not criticizing the very idea of synthesizing archaeological data and organizing it into big historical narratives, as Wray and Smith have tried to do, just pointing out the flaws in the way they and some other archaeologists go about doing this. (This part is interesting because Wedel himself would go on to become one of the most important synthesizers of the archaeology of the Great Plains.)

Welcome Sign, Kaskaskia, Illinois

As it turns out, Wedel was more or less completely right on every point he criticized Wray and Smith about, and the much more complete and accurate picture we now have of Midwestern archaeology has vindicated him. The point is not that Wray and Smith were wrong so much as that they were sloppy; it’s always going to be the case that even many very reasonable interpretations based on the best data available at one time will turn out to be wrong when better data appears, but not all interpretations at any given point in time are necessarily based on the best data or the most reasonable assumptions. This little dispute provides a particularly clear example of this general point.
Blasingham, E. (1956). The Depopulation of the Illinois Indians, Part I Ethnohistory, 3 (3) DOI: 10.2307/480408

Blasingham, E. (1956). The Depopulation of the Illinois Indians. Part 2, Concluded Ethnohistory, 3 (4) DOI: 10.2307/480464

Wedel, W. (1945). On the Illinois Confederacy and Middle Mississippi Culture in Illinois American Antiquity, 10 (4) DOI: 10.2307/275581

Wray, D., & Smith, H. (1944). An Hypothesis for the Identification of the Illinois Confederacy with the Middle Mississippi Culture in Illinois American Antiquity, 10 (1) DOI: 10.2307/275179

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