One of the major advantages Southwestern archaeologists have over those studying other areas of prehistoric North America is a very solid chronology, based primarily on tree-rings and extended by diagnostic pottery types that in many cases changed rapidly. As a result of this chronology, in many parts of the Southwest unexcavated sites can be dated to within a century or less based purely on the potsherds found on the surface. This is not the case in most other parts of North America, where dating is based primarily on radiocarbon dates, which are inherently less precise than tree-ring dates, and where the pottery types are often less solidly defined and/or less securely tied to the sequence of absolute dates. In recent decades, however, the development of more precise radiocarbon dates through the accelerator mass spectrometry (AMS) technique and the further refinement of artifact typologies have allowed archaeologists in many areas to get a better sense of cultural dynamics over time.
One of the areas where this has been particularly the case is the southeastern US, where the late prehistoric period is marked by the rise and fall of a wide variety of societies noted for their large platform mounds, extensive use of maize agriculture, and distinctive iconography indicative of a widespread set of ideological beliefs and social structures. These societies are known as “Mississippian,” and while much remains to be known about them, we know much more about them now than we did fifty years ago. They are generally considered to have had a “chiefdom” form of society, less complex than a state but more so than a band or tribe, although an increasing number of Southeastern archaeologists have been questioning the whole concept of chiefdom and of this typological approach to societal complexity in general. Be that as it may, it’s quite clear that the leaders of most Mississippian communities had quite a lot of control over their fellows, as shown by the amount of labor they could control to build the platform mounds (which in Mississippian communities generally served as bases for elite residences and temples, a striking difference from the more communal ritual purposes that mounds had served in many earlier societies) and their elaborate burial ceremonies and grave goods.
The greatest Mississippian center, by far, was Cahokia, in the American Bottom region of west-central Illinois across the Mississippi River from what is now St. Louis. I’ve written a bit about some recent work on the origins of Cahokia, but while it’s a really spectacular site (well worth a visit) it’s important to note that there were many other Mississippian centers, none of them quite on the same scale as Cahokia but many of them pretty important and impressive themselves. Among the most important of these in the area surrounding the confluence of the Ohio and Mississippi Rivers, south of Cahokia, were:
- Kincaid, in far southern Illinois, across the Ohio River from the modern city of Paducah, Kentucky
- Angel, further up the Ohio in what is now Evansville, Indiana
- Wickliffe, a smaller center in what is now Wickliffe, Kentucky, right at the confluence of the Mississippi and Ohio
- Shiloh, further south, on the Tennessee River at the site where the Civil War battle of Shiloh would later be fought
After the introduction of radiocarbon dating in the late 1940s, the chronology of occupation at these sites gradually became clearer. It now appears that Cahokia, despite being the biggest and most impressive Mississippian center, was relatively early in the sequence, with its major building period beginning in the eleventh century AD and continuing into the twelfth, but declining after then and becomingly largely empty by about 1350. Kincaid and Angel, which emerged later than Cahokia, lasted a bit longer, but both seem to have been abandoned by about 1450. The other, smaller centers in the region seem to have similar trajectories, with occupation appearing to end at various points but never later than 1450 or so.
It’s notoriously difficult to date the end of anything by archaeological means, but the widespread lack of post-1450 dates throughout the confluence area is certainly suggestive, especially since it is not universal among Mississippian societies. Indeed, many Mississippian centers further south and east continued to be occupied after 1450, and some were still there when the De Soto Expedition showed up in the sixteenth century (and wreaked sufficient havoc to destroy most of them, but that’s another story).
This apparently total but geographically limited abandonment of some of the largest river valleys on the continent led one archaeologist, Stephen Williams of Harvard, to propose in the early 1980s that this region constituted a “Vacant Quarter” starting sometime between 1450 and 1550 and continuing into the historic period. Williams defined the Vacant Quarter as starting with the American Bottom, extending south along the Mississippi to its confluence with the Ohio (but, importantly, no further south), then up the Ohio as far as Angel and up the Tennessee as far as the Mississippi and Alabama borders. Part of his argument for the vacancy of this area was the total lack at major sites within it of certain artifacts he had found at sites in northeastern Arkansas that he considered temporal markers for the very late prehistoric period. While these or similar objects were also found in other areas further away that are known to have been occupied at this time, including Alabama and Wisconsin, they are conspicuously absent from Kincaid, Angel, Cahokia, and other major sites along the Mississippi, Ohio, and Tennessee. In his early formulations of the concept, however, Williams did acknowledge that his information came entirely from large sites in the major river valleys, and that more study might show that smaller sites in the surrounding uplands may have been occupied later.
Charles Cobb and Brian Butler went on to test this idea in their fieldwork in the uplands of southern Illinois, and they published their results in 2002. What they found was that Williams’s Vacant Quarter hypothesis held for these upland areas as well. The sites they excavated were smaller than the large riverine centers, but the many radiocarbon dates they had acquired showed the same pattern: little to no occupation later than 1450, and abandonment possibly even earlier.
The fact that abandonment appears from this data to have been essentially complete within the Vacant Quarter, regardless of environmental setting, suggests that while climatic changes associated with the Little Ice Age (one explanation that has been offered for the abandonment of the area) may have had something to do with the abandonment, whatever changes occurred must have been sufficiently severe to affect basically everyone in the area, but not people in surrounding areas with generally similar conditions. To me this suggests that environmental changes were not the main cause of the abandonment, but it is quite possible that they played a role in catalyzing changes that also had to do with social and political dynamics. Persistent drought, which can be quite localized, is a possibility, although it would have to take one hell of a drought to force farmers to abandon what was (and is) one of the most productive agricultural areas in the world. More likely, perhaps, as an environmental cause is severe flooding, which as we’ve seen in recent years can be a major problem in this region. When I was traveling through it this summer the effects of recent flooding were very apparent. Still, it’s not clear why this would have affected the Vacant Quarter but not the surrounding areas.
Finally, as ever with abandonment scenarios, there is the question of where the people went. In the case of Angel, this seems to be apparent. Around the same time the Angel center was abandoned, a new occupation seems to arise a short distance downstream, around the confluence of the Ohio and the Wabash near what is now the Illinois-Indiana border. This is known as the Cabon-Wellborn phase, which is generally Mississippian in culture but lacks platforms mounds and extends well into the protohistoric period, as late as 1650 or even later. Cobb and Butler seem to think this represents the descendants of the people who lived at Angel, and I see no reason to doubt this. The other parts of the Vacant Quarter seem to lack comparable descendant communities, which suggests that they went somewhere else, perhaps joining the surviving Mississippian centers to the south or the quasi-Mississippian Oneota groups to the north.
Cobb and Butler note that while the Vacant Quarter is a particularly dramatic example of regional abandonment, such events are not unusual in the archaeological record of the Eastern Woodlands. They suggest that this was a fairly common occurrence, and that it should receive more study than it has. They specifically refer to the Southwest as a region where similar abandonments are widely accepted and intensively studied, and imply that Southeasternists could follow this lead in trying to explain these events. Their own guess about the Vacant Quarter specifically is that “climatic deterioration or other causes may have exacerbated a competitive and often hostile political environment that rendered the region less hospitable,” which sounds good to me.
The major mound sites of the US Midwest and South have been objects of considerable interest for well over a century, but it is only in recent decades that modern archaeological techniques have begun to unravel the undoubtedly complicated stories behind them. There’s still a very long way to go before we have a clear picture of what these societies were like and what happened to them, but we’re getting closer all the time.
Cobb, C., & Butler, B. (2002). The Vacant Quarter Revisited: Late Mississippian Abandonment of the Lower Ohio Valley American Antiquity, 67 (4) DOI: 10.2307/1593795