Where They Got the Obsidian

Mt. Taylor from Chaco

As I’ve discussed before, the patterns of use and importation of chipped stone at Chaco are somewhat puzzling. Unlike many other commodities, such as wood, corn, and pottery, which were imported from specific distant locations within the Chacoan sphere of influence in astonishing quantities during the height of Chaco’s regional power, chipped stone seems to have been largely a mundane, utilitarian concern. Throughout all periods of Chaco’s occupation most chipped stone was local. At Chaco’s peak of power and influence between AD 1020 and 1130 there was a slight uptick in imports of stone, particularly a distinctive pink chert from the Narbona Pass area to the west.

As I noted in the earlier post, however, obsidian follows a different pattern from the other imported stones. It is most common not at the height of Chaco’s regional power in the eleventh century but much earlier, in the Basketmaker III period between AD 500 and 750, when it is the most common nonlocal type of chipped stone. This was a time when Chaco may have seen an earlier period of regional importance, although figuring out what was going on at this time is very difficult for several reasons. By the Pueblo I period the amount of obsidian seems to drop precipitously, and it doesn’t start to recover until the very end of Chaco’s period of Pueblo occupation after AD 1120. This pattern puts obsidian decidedly out of phase with most other material culture imports to the canyon, which tend to correlate with the well-known evidence for social complexity and monumental architecture that we associate with the Chaco Phenomenon.

A recent paper by Andrew Duff, Jeremy Moss, Tom Windes, John Kantner, and Steven Shackley tries to put the obsidian evidence on a firmer footing by using geochemical sourcing to identify the source outcrops for a broad sample of obsidian found at Chaco and at various Chacoan outlier communities in the San Juan Basin. As they note, this is the latest chapter in a complicated story. Way back in the 1980s, the Chaco Project did an extensive sourcing study of obsidian found in its excavations in the canyon using X-ray fluorescence (XRF), a non-destructive sourcing technique that was then relatively new in archaeology. Their results, reported by Cathy Cameron in a number of publications, were surprising. They seemed to show that the closest source of obsidian, Mt. Taylor, provided very little of the obsidian found at Chaco (about 4%), while a distant source, Red Hill in Catron County, New Mexico, provided a very high proportion, especially in the assemblages from earlier sites. Also well-represented was obsidian from the Jemez Mountains, the second-closest source, with the proportion of Jemez obsidian increasing over time, a common pattern in the northern Southwest.

This seemed to indicate that there were substantial early ties between Chaco and the Red Hill area, far to the south but still just barely adjacent to some known Chacoan outliers. This result was mentioned in many publications on Chaco over the years, although many people didn’t really seem to know what to think of it. However, it soon began to be questioned. After this initial sourcing study had been done, Tom Windes submitted some samples of obsidian from Pueblo Alto and the Spadefoot Toad site for obsidian hydration dating, which involved a sourcing analysis as an intermediate step in the dating process. These analyses were inconclusive when it came to dating the artifacts (not uncommon in the Southwest, where obsidian hydration has a poor record as a dating technique), but the sourcing portion suggested strongly that the samples that had previously been sourced to Red Hill instead came from Mt. Taylor. Windes mentioned this anomaly in his site reports, as did Cameron in her subsequent publications on the subject, but a full published account didn’t appear until this new study.

The new study also used XRF to do the sourcing analysis, but both analytical techniques and source characterizations have improved considerably since the 1980s, so the results were quite different from the first effort. For some reason this study was unable to do a complete reanalysis of the earlier samples (although it implies that this may be possible in the future), so there was only limited overlap and the focus was mostly on recent samples collected by Windes at Basketmaker III and Pueblo I site in and around Chaco, as well as outlier sites studied by Kantner in the Red Mesa Valley near Mt. Taylor and by Duff at the southern edge of the Colorado Plateau near Red Hill.

The results were not really surprising, in that they have been known in broad outline since Windes submitted his samples for dating and reported on the sourcing anomalies, but it’s nice to see them formalized in a peer-reviewed paper. Basically, this study found that no samples from Chaco came from Red Hill, although a few came from other sources in the same general area, and that the most common source found at Chaco was Mt. Taylor. Over time there was a trend in the Chaco data showing a shift from Mt. Taylor to Jemez sources, accompanied by the well-known trend toward less obsidian in assemblages overall. The sample from the Blue J site near Mt. Taylor, in contrast, showed high proportions of Mt. Taylor obsidian increasing over time, in marked contrast to the Chaco pattern. The southern sites showed assemblages of obsidian almost entirely composed of Red Hill and other nearby sources.

Basically, the overall pattern was a classic distance-decay distribution, where the prevalence of a given source at a given site was mostly predictable by the distance between the source and the site. This is in sharp contrast to the pattern for many other imported goods at Chaco, which are present in high quantities in the source areas and at Chaco but not in between. This suggests strongly that obsidian was not part of any general Chacoan exchange system(s) but was procured by individual communities in accordance with their own needs, mostly using the closest sources. This is in keeping with the general tendency for chipped stone to be a relatively low-priority commodity in these societies.

The paper mentions the decline in overall abundance of obsidian after the Basketmaker III period at Chaco, but doesn’t spend much time discussing it beyond saying this:

The overall decrease in obsidian use noted at Chaco sites may reflect a shift in technological focus away from hunting and a subsequent focus on grinding technology as agriculture becomes the dominant subsistence strategy.

As I’ve noted before, this is almost certainly wrong; the decrease in question occurs at the end of the Basketmaker III period, at which time there is considerable evidence that Southwestern populations were already heavily dependent on agriculture. The decrease in obsidian is still odd, though. One thought I’ve had to explain it is that maybe the obsidian from after this period isn’t actually missing at all, but is at Pueblo Bonito, which had lots of obsidian but was excavated a long time ago using techniques that aren’t really comparable to the modern techniques used by the Chaco Project and later efforts that resulted in the collections being analyzed here. I would suggest that an XRF sourcing analysis of the Bonito obsidian would be interesting. As it is, there’s a huge shift in the proportions of the different sources at Chaco between Basketmaker III and Pueblo I. The earlier samples (dominated by the huge samples from the major villages of Shabik’eschee and 29SJ423) show a predominance of Mt. Taylor obsidian, while the later ones show mostly Jemez sources. The sample size is so much smaller for the later period, however, that I’m skeptical about taking this flip at face value. Including the Bonito assemblage might help to bridge this gap, or at least explain it.

Finally, it’s again noteworthy how unimportant obsidian appears to have been to the Chaco system. Even if the Pueblo Bonito evidence ends up indicating a more important role at Chaco itself, the various outlier communities appear to have used local sources and to have followed their own priorities in acquiring this commodity rather than getting it through any Chaco-controlled or -oriented system. This is one of the ways that Chaco appears to diverge from Mesoamerican societies, despite recent evidence that it may have had more contact with them than was previously believed. Obsidian was hugely important symbolically in Mexico, and control of major sources was a major source of power and wealth for various Mesoamerican polities. In the Southwest, however, nobody seems to have cared that much about controlling major obsidian sources, and obsidian seems to have been distributed as a fairly ordinary commodity without any particular symbolic importance. I think this is one of the strongest pieces of evidence suggesting that whatever influence Mesoamerican societies may have had on Chaco was indirect and mediated by Chacoan elites rather than imposed directly from Mexico, as some have argued.

In any case, while this isn’t really the most exciting paper, it’s still an important one in straightening out a part of Chacoan archaeology that had become pretty confused. Obsidian may not have been all that important at Chaco, but it’s still worth studying in part precisely because of its mundanity.

Duff, Andrew I., Moss, Jeremy M., Windes, Thomas C., Kantner, John, & Shackley, M. Steven (2012). Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence Journal of Archaeological Science, 39 (9), 2995-3007 DOI: 10.1016/j.jas.2012.04.032

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Wetherill’s Intellectual Influence

Richard Wetherill’s Grave

Today is Wetherill Day, the anniversary of Richard Wetherill’s death in 1910, and as such I would like to continue my tradition of marking the occasion by discussing the complicated and often misunderstood legacy of Wetherill, the pioneering amateur archaeologist who excavated many sites in the Southwest, including most famously Pueblo Bonito at Chaco Canyon. I’ve talked about the general story and context in previous posts, so this time I’d like to note one specific example of how, in contrast to his popular image as a simple pot-hunter focused on collecting artifacts, Wetherill made some quite perceptive (though not necessarily correct) deductions about cultural history based on his excavations.

After his early work in the 1880s at Mesa Verde, near his family’s ranch outside the small town of Mancos, Colorado, but before his more famous work at Chaco between 1896 and 1901, Wetherill did some exploring of the cliff dwellings of the Grand Gulch area of southeastern Utah. By this point in his career Wetherill had become quite sincerely interested in archaeology not just as a source of articles to be sold but as a window into the past, and his techniques of both excavation and interpretation had improved markedly, in part due to influence by the Swedish archaeologist Gustaf Nordenskiöld, who had come to Colorado in 1891 and assisted with the Mesa Verde work.

In the winter of 1893–1894, Wetherill organized an expedition to Grand Gulch with the financial backing of the wealthy New York brothers Benjamin and Talbot Hyde. This was the first instantiation of the Hyde Exploring Expedition, which would later become the aegis for Wetherill’s work at Chaco as well. As James Snead notes in an article on the relationship between Wetherill and the Hydes:

The principal archaeological discovery of the season was of remains predating those of the “cliff dwellers,” which Talbot Hyde, exercising a prerogative of sponsorship, named the “Basket Makers.”

And Basketmakers they remain; the term is still in use to designate this culture, which did indeed predate the later groups of “cliff dwellers” who built stone houses and are therefore known as “Pueblos.”

But how did Wetherill and the Hydes know that the Basketmaker remains they found at Grand Gulch predated the cliff dwellers? Through the use of stratigraphy, which is based on the assumption that in undisturbed deposits lower layers are older than higher ones. The Basketmaker deposits were below the cliff dweller ones, therefore they were older. There have been suggestions that Wetherill actually used stratigraphic excavation at this time, which is to say that he used stratigraphic levels as the organizing principle for the excavation itself, but David Browman and Douglas Givens argue in an article on the rise of stratigraphic excavation in American archaeology that there is no evidence he actually did. Instead, he most likely excavated and only afterward looked at the strata in the exposed trenches to make his cultural determinations, a fairly common practice at the time which Browman and Givens call “post facto stratigraphic interpretation” and oppose to the truly stratigraphic excavation that arose in the 1910s.

But Wetherill didn’t just notice that the Basketmaker remains were different from and lower than the cliff dweller ones. He also came up with a tentative theory on the relationship between the two groups. Based on both artifact differences and, as Erik Reed discusses in an article on the early history of physical anthropology in the Southwest, skull shapes, Wetherill concluded that the two groups were “racially” distinct, with the implication that the one was not descended from the other. As Reed notes, this was challenged a bit by other archaeologists at the time, but later discoveries seemed to confirm it, and it became dogma in the early twentieth century until further research in the 1940s showed that the differences in skull form were actually due to artificial cranial deformation in the later skulls probably caused by the introduction of stiff cradleboards. It was further found that there were actually multiple kinds of such deformation, of possible significance in delineating different cultural groups. Reed says:

The very significant distinction between lambdoid and vertical occipital cranial deformation was brought out only in 1937, by T. D. Stewart, followed up by my 1949 paper; but was foreshadowed by Richard Wetherill who stated [...] ”that there is a difference in the mode of flattening the head. In the skulls of the mesa dwellers the artificial depression of the posterior part of the cranium has been applied obliquely from above, so that it principally affects the parieto-occipital region; the skulls from the cliff-dwellings have been flattened straight from behind, the occipital region being most affected.”

The distinction between the Basketmakers and cliff-dwellers on stratigraphic grounds was an important discovery, and while it was the sort of thing that many professional archaeologists would likely have noticed at the time, it’s not something a typical pot-hunter would have cared much about. Wetherill, however, not only noticed it but drew some reasonable if ultimately erroneous inferences about population history from it. He also noticed some subtle differences in skull form and attributed them to different types of cranial deformation, which was later found to be quite correct (although note that he doesn’t seem to have considered that this might have been the reason for the differences between Basketmaker and later skulls as well). Wetherill was a problematic guy in a lot of ways, as my previous posts have noted, but when it comes to archaeological methodology and inference he was definitely at the forefront of the archaeological thought of his time, if not in fact ahead of it.

Browman, David L., & Givens, Douglas R. (1996). Stratigraphic Excavation: The First “New Archaeology” American Anthropologist, 98 (1), 80-95 DOI: 10.1525/aa.1996.98.1.02a00080

Reed, Erik K. (1963). The Beginnings of Physical Anthropology in the Southwest Journal of the Arizona Academy of Science, 2 (3), 130-132 DOI: 10.2307/27641802

Snead, James E. (1999). Science, Commerce, and Control: Patronage and the Development of Anthropological Archaeology in the Americas American Anthropologist, 101 (2), 256-271 DOI: 10.1525/aa.1999.101.2.256

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Steve Lekson Hearts Jared Diamond

Chaco Wash and Escavada Wash Near Their Confluence

I’ve never read any of Jared Diamond‘s books, so I’ve been reluctant to say much about him and his ideas.  Chaco is one of his main case studies in Collapse, however, so I really should read it at some point and try to figure out what I think of it.  I’ve heard conflicting things about how accurately it presents and interprets the evidence he gathers from archaeologists.  A lot of people seem to really like it, but most archaeologists seem to hate it and think that it’s riddled with errors.  I browsed through it a little once in the Chaco bookstore (which, yes, carries it, or at least did at the time), and I didn’t see any obvious errors of fact in the parts of the Chaco chapter I looked at, but the caption for one of the pictures, an overview of the canyon as it appears now, seemed to imply that the current desolate look of the area was the result of the overexploitation of the local environment by the Chacoans, which presumably led to their collapse.  My understanding of Diamond’s message, based mainly on the subtitle of the book (“How Societies Choose to Fail or Succeed”), is that the main driver of collapse he sees is environmental degradation, and the book’s popularity in environmentalist circles certainly makes sense in this light.

In any case, I’m skeptical about the whole idea that Chaco “collapsed” in the way that Diamond seems to think.  I’ve put forth my case in detail elsewhere and won’t repeat it now, but the basic idea is that what happened at Chaco is more complicated than a simple catchword like “collapse” (however it’s defined) implies.  On the narrow point of whether whatever happened at Chaco was the result of “choices” the Chacoans made about whether to “succeed or fail,” I guess it depends on what choices you mean by that.  David Stuart argues that the rigid, hierarchical social structure that allowed Chaco to become so impressive in the first place made the system too brittle to withstand severe climatic fluctuations, with the result that it was replaced by the more egalitarian and resilient social structures of the modern Pueblos.  He sees some clear lessons for our own society from this, primarily about the problems with economic inequality (a timely topic these days).  That’s one way of looking at “collapse.”

Southeast Corner of Pueblo Bonito

I’m not sure if it’s what Diamond is talking about, though.  I’ve seen him described as an “environmentalist” in the old sense, i.e., an environmental determinist who sees major aspects of human societies as inevitable results of their environmental situations, with the twist that he obviously doesn’t have a completely deterministic view of human reactions to the environment but rather, more in line with the modern meaning of “environmentalism,” he recognizes that the interaction between humans and their environments goes both ways.  Under this view, presumably the most enlightening examples of past “collapses” to look at for insights into how we should address our own environmental problems are those where collapse was the result of ecological “overshoot,” or human use of natural resources outstripping the ability of the environment to provide them.  Joseph Tainter, who knows a lot about “collapse” from an archaeological perspective, has vigorously criticized Diamond’s (and others’) use of this approach, and I think choosing Chaco as an example of this type of collapse is particularly questionable.

It’s not that the Chacoans didn’t have major effects on their local environment.  The permanent resident population of the canyon may not have been very large, but it’s not an area that’s exactly abounding in resources, and the fact that the Chacoans imported all kinds of stuff from outside the canyon strongly implies that there wasn’t enough of all sorts of things locally to support the community.  I believe Diamond makes a big deal specifically out of the evidence for importing wood from the distant mountains, which I presume he sees as evidence that the Chacoans had deforested their local area more or less completely, with the attendant implications for overshoot and collapse.  Hence the caption on the picture I noticed when leafing through the book: the implied sequence of events is rise of Chaco leading to deforestation leading to collapse leading to a treeless desert wasteland even 1000 years later.

Intact Roof at Pueblo Bonito

But of course the evidence for importing timber from 50 miles away also implies that the Chacoans had the ability to organize some seriously impressive procurement for those resources they were lacking locally (whether because they had outstripped them or because they were never there to start with).  It’s not that they didn’t deforest their local area; they totally did, and fast!  But if that had been enough to make the system collapse, it never could have gotten going in the first place.  The abiding mystery of Chaco, after all, is not that a major center of its scale arose in the Southwest but that it arose where it did, in one of the least inviting environments in the whole region.  Somehow, the people at Chaco were able to marshal the resources of a much bigger area with many more resources, until suddenly they couldn’t.  The thing that needs to be explained by any “collapse” narrative is why that social power stopped so abruptly, which presumably also requires an answer to the question of how it developed in the first place.  We don’t know the answers to any of these questions, which is why Chaco remains such a fascinating and mysterious place even after over a century of intensive study.

“Overshoot” is not a very helpful explanation in this context.  Stripping the canyon of all its productive potential clearly didn’t lead to the collapse of Chaco, as the Chacoans were able to draw on the much greater potential of the whole region, at least for a while.  Overshoot doesn’t really explain why that control ended, either, since the overall resources of the region that the Chacoans apparently had access to were much too abundant for them to deplete.  They easily deforested the mesas above the canyon, but they never came close to deforesting the Chuskas or Mt. Taylor.  Those are big mountains, covered in trees!  And the same goes for all the other imported goods.  You could perhaps make a case for overshoot in some particular area perhaps contributing to the collapse of Chacoan power in some roundabout way, but it would definitely not be as simple as a straightforward story of overshoot leading to collapse implies.  That picture doesn’t show the enduring effects of Chacoan deforestation on the canyon; it shows what the canyon probably looked like when the Chacoans first encountered it.  Indeed, the canyon ecosystem we see today is the result of over fifty years of protection from grazing, and over a hundred years of protection from most other impacts.

Juniper Trees on the South Mesa Trail

So those are my thoughts on Diamond, and I really should read the book at some point to get a better sense of what he actually argues and whether this is a fair interpretation.  What I find interesting, though, is that noted archaeological iconoclast Steve Lekson has recently written an impassioned post in support of Diamond.  He points out that most archaeologists seem to hate Diamond’s books and spend a lot of time pointing out the flaws in them, but he argues that doing this is missing the more important point:

I’m sure there are errors – real errors.  Any work of this scope will have errors.  But much of the carping seems to concern not facts, but interpretations.  Diamond necessarily works from other archaeologists’ interpretations and I suspect the authors upon whom he relies would have something to say about all this.  The interpretations he accepts are not necessarily wrong; they are simply inconsistent with those of his critics.

I’m not saying that Diamond gets it “right.”  It’s hard to get things completely “right,” especially in science when many very reasonable hypotheses are probably wrong.  But the vehemence of academic reaction to Diamond is, I think, far disproportionate to his sins – sins of omission, commission or (worst of all) failure to cite the critic.  It is my opinion that much of the heat comes from Diamond’s success as a popular writer.  It’s not jealousy — well, maybe a little: after all, the guy won the Pulitzer with our data.  We don’t want anyone else to tell our story, even though we almost never tell it ourselves – accessibly.  And, it must be said, there is antipathy, even hostility from academics towards popular writers, even when that popular writer is an academic.     We all should re-read Article 4 of the SAA’s Principles of Archaeological Ethics, especially the bit about “Archaeologists who are unable to undertake public education and outreach directly should encourage and support the efforts of others in these activities.”

Fair enough.  I do obviously agree with the value of outreach and it’s true that Diamond has been a wildly successful popularizer of archaeology.  Lekson goes on to give a very interesting account of what he sees as the important “collapses” in Southwestern prehistory.  I note that Chaco, specifically, doesn’t appear on the list, although the depopulation of the Four Corners around AD 1300 does.  I have my doubts about that one too, but it really depends a lot on how you define “collapse.”  It’s not clear if Lekson has actually read Diamond’s book(s) (although obviously I’m hardly one to judge on that score), and he doesn’t directly address any of Diamond’s claims or interpretations about Chaco specifically, even though he is of course much more of an expert on Chaco than either Diamond or me.  Still, his general points about the reaction to Diamond are fair.  It would probably be more helpful for archaeologists who object to interpretations of their data put forth in popular accounts like Diamond’s to explain their objections in similarly popular fora, rather than just whining amongst themselves.  Diamond’s work may have a lot of problems, but at least he’s trying to draw conclusions from archaeological data and apply them to modern issues in accessible way, which is much more than you can say for most archaeologists, with a few notable exceptions like Stuart and, to a lesser extent, Lekson himself.  In any case, I think it’s clear that this conversation is really just getting started, so anyone who is really upset by the direction it’s taken so far has plenty of opportunity to jump in and contribute a different perspective.

View from Doorway at Pueblo del Arroyo

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Chaco Preservation Crew Makes the News

Chaco Preservation Crew Repairing Masonry at the Fort Site

Today’s Albuquerque Journal has an article, originally published in the Gallup Independent, about the Chaco preservation crew and their work maintaining the various sites in the park.  The article focuses specifically on recent work they’ve done at Pueblo Pintado.  I don’t have a whole lot to add, but it’s an interesting account that addresses some of the complications of doing this sort of work for traditional Navajos, who have a strong taboo against even visiting Anasazi sites.  The article says that the crew deals with this in part by conducting prophylactic ceremonies before starting work on the sites, which I hadn’t known.  These ceremonies are apparently led by Harold Suina, a member of the crew who is from Cochiti Pueblo and is not Navajo (although I believe his wife is, and they live near Chaco in an area inhabited almost entirely by Navajos).  The article doesn’t say this, but I suspect that Harold’s role is particularly important since Pueblos like Cochiti have different attitudes toward the sites at Chaco than Navajos do, so he may not feel as uncomfortable dealing with them as the other members of the crew, all of whom are Navajo, do.  Not all of the Navajo members of the crew are traditional, however; some are Christian, as are many Navajos in the Chaco area, and they may not have the same qualms about their work that their more traditional colleagues have.

Anyway, it’s an interesting article, and it’s nice to see the preservation crew getting some media attention.  They do crucial work for the park, but it rarely gets noticed by either visitors or the many people who have written books and articles about Chaco over the years.  When I was doing tours I would usually do a fairly detailed description of the preservation work early on in the tour, both because people often want to know how much of what they see at the sites is reconstructed (at Chaco, very little, unlike at many other parks) and because I wanted them to appreciate how much work it is to maintain the sites and why it is therefore important for them as visitors to treat them respectfully and minimize the amount of damage they cause.  Hopefully this article will serve a similar function for a wider audience.

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The Stars Bursting in Air

"Supernova" Pictograph

Happy Fourth of July, everyone.  The Fourth is actually a pretty important date for the study of Chaco, but in a roundabout (and somewhat controversial) way.  It all has to do with a very famous pictograph panel below Peñasco Blanco at the west end of the canyon.  While the interpretation of this panel is a matter of considerable debate, one way it’s been seen is as a record of an astronomical event that is known to have occurred during the height of Chaco’s power and influence: the supernova of 1054, which formed the Crab Nebula.

We know from several Chinese reports that the “guest star” resulting from the supernova first appeared on July 4, 1054 and continued to be visible day and night for almost two years.  There are a few Japanese records of the supernova as well, along with one report from the Arab world.  No clear-cut and unambiguous accounts are known from Europe or elsewhere in the world, although a few rock art panels in the Southwest have been proposed as representing the event.  The most famous of these is the one at Chaco, which is often referred to as the “Supernova Pictograph” (even by the park itself in a sign at the site).  It consists of three symbols painted onto the rock face in red: a hand, a crescent, and a starburst-like shape.  It’s the starburst that has been interpreted as representing the supernova itself, of course, and the crescent has been seen as representing the crescent moon.  On the morning of July 5, the moon, which was a crescent at the time, would have appeared in roughly the same relationship to the supernova, as seen from the pictograph site, as the relationship between the two symbols on the panel.  Furthermore, the handprint points in the direction one would have looked to see this at at the time.  The combination of the three symbols together, plus the fact that this would have happened at a time of considerable activity in the canyon, has led some to suggest that this pictograph panel was created to commemorate this historic event.  The specific location may have been an established sun-watching position, from which the new star was seen unexpectedly and recorded.

Sign at the "Supernova Pictograph"

It all sounds fairly plausible as it goes, but there are some problems with this theory.  Probably the biggest problem is that the specific set of symbols on the panel is known from ethnographic evidence to have been used by the Zunis to mark generic sunwatching sites, with the crescent representing the moon, the starburst representing the sun, and the hand marking the location as sacred.  Now, it’s certainly possible that these symbols came to be associated with this activity as a result of the observation of the supernova at this site, but as far as I know there’s no reference to the supernova in ethnographic descriptions of astronomical observation at Zuni or any of the other modern Pueblos, so this is a pretty tenuous claim.

Furthermore, while the 1054 supernova would certainly have been noticeable at Chaco, there was an earlier supernova in 1006 (also recorded by the Chinese, and possibly by the Hohokam in southern Arizona) that was much brighter, and it’s not clear why the Chacoans wouldn’t have recorded that one too.  It took place before the Chaco system really got going on a regional scale, but there was plenty of activity in the canyon during the 900s, so people there would presumably have seen it.  It’s possible that it was recorded too, at some other site that hasn’t been found or that has disappeared in the thousand years that have elapsed since the event (note that the existing Supernova Pictograph has only survived because it was under a protective overhang), but again, there’s not any evidence for this.  The Chacoans are definitely known to have kept careful track of regular patterns in the skies, such as the solstices and the lunar standstills, so they surely would have seen unusual events such as supernovae, but it’s not clear how they would have reacted to them or how inclined they would have been to record them.

View Looking East from "Supernova Petroglyph"

So it’s not really clear how to interpret the Chaco pictograph.  I think the balance of evidence at this point leans slightly against it being a representation of the supernova, but I could be talked out of that position if some additional evidence for the supernova theory can be found.

Others, however, have proposed even more extreme theories based on the 1054 supernova.  Among the more noteworthy of these is a proposal by Timothy Pauketat and Thomas Emerson, in a 2008 article in the Cambridge Archaeological Journal, that the rather sudden florescence of the Cahokia site in Illinois around AD 1050 may have had something to do with the supernova.  The theory they present is interesting, but hard to effectively support.  For one thing, dating methods in the Midwest are much less precise than in the Southwest, so pinning down any event to the year is usually not possible.  There is certainly a suggestive correspondence between the sudden rise of Cahokia and the supernova, however, and this is supported by the apparent use of stellar imagery and symbolism at Cahokia and the importance of the stars to later cultures in the area, so there may well be something to this.

Opening at Casa Rinconada That Channels Sunbeam at Sunrise on Summer Solstice

I’m a bit troubled, however, by the reliance of Pauketat and Emerson on evidence from Chaco and the way they interpret it.  For one thing, they say that the Supernova Pictograph is “above” Peñasco Blanco, when it’s actually below it, and not visible from the great house itself.  More importantly, they say of the effect of the supernova:

Some believe that this particular cosmic event, which left behind the Crab Nebula, was commemorated in architecture and iconography at the time or in subsequent years. The most compelling evidence for this comes not from the Cahokia region but from the American Southwest, where a tree-cutting date places the construction of the largest and most isolated ceremonial building in Chaco Canyon, Casa Rinconada (noted for its many astronomical alignments) to AD
1054.

Now, it’s true that there is a single tree-ring cutting date from Casa Rinconada that dates to 1054.  This is, however, the only tree-ring date for the site, so while it’s plausible that it dates the construction of the site this definitely cannot be stated as definitively as Pauketat and Emerson state it here.  There is no specific provenience information available for this beam, so there’s no way to tell how it was used and whether it can plausibly be said to date to the initial construction of the site.  The general architecture of Casa Rinconada is consistent with a construction date in the 1050s, but without more specific information tying it to a specific year on the basis of one unprovenienced beam is unwarranted.

Looking through Solstice-Aligned Opening at Casa Rinconada toward Aligned Niche

Furthermore, even if Rinconada was built in 1054, that doesn’t establish that it was built because of the supernova.  There was extensive construction in the canyon throughout the mid-1000s, associated with Chaco’s apparent rise to regional dominance, and this began well before 1054.  The major expansion of Pueblo Bonito began by the 1040s at the latest, and various other construction projects at other sites in the canyon dates to this general period.  Rinconada could easily have been part of this general process without any specific relationship to the supernova.  Indeed, there’s nothing about Rinconada that seems to refer to the supernova, despite the various astronomical alignments (some of them controversial as well, it should be noted) identified there.

None of this means that the supernova didn’t have an important role at Cahokia, of course, and it doesn’t even rule out an important role at Chaco itself.  It does mean, however, that developments at Chaco shouldn’t really be used as evidence for developments at Cahokia, even though the two sites are contemporaneous and Chaco can be dated much more precisely.  Cahokia may well have risen as a result of the 1054 supernova, but neither the Supernova Petroglyph at Chaco nor the one tree-ring date at Casa Rinconada provides evidence that it did.

Pauketat, T., & Emerson, T. (2008). Star Performances and Cosmic Clutter Cambridge Archaeological Journal, 18 (1), 78-85 DOI: 10.1017/S0959774308000085

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Steve Lekson’s Ancient Southwest

Sign at State of New Mexico Archives Building, Santa Fe, New Mexico

Several months ago Steve Lekson sent me a review copy of his latest book, A History of the Ancient Southwest.  I recently got around to reading it, and it’s very good.  The importance as well as the idiosyncratic nature of this book begins with its title.  While the title sounds generic, it’s actually carefully chosen and worded, and in a subtle way it expresses the unusual approach Lekson takes to Southwestern archaeology, not just in this book but in many of his other recent publications.

The crucial thing about the title, and about the book, is the word “history.”  This book is both an attempt to tell the story of what happened in the ancient Southwest, and thus a “history” of the Southwest in ancient times of the sort an historian might write, and a parallel attempt to tell the story of the development of Southwestern archaeology as a (sub)discipline, i.e., a history of “the ancient Southwest” as an idea and of the ways that idea has been studied and interpreted over time.  The title also refers, quite deliberately, to a book with the same title that Harold Gladwin published in 1957.  Gladwin’s a fascinating character, as is Lekson himself in his own way, but in this context the most important thing about him is his fondness for synthesizing archaeological data and presenting it as an accessible narrative.  Lekson is seeking to do the same thing in this book, and he mostly succeeds.  This is a more impressive accomplishment than it sounds, because summarizing the entire prehistory of the Southwest in narrative form is an astonishingly ambitious project, and there’s a reason no one else has tried to do it since Gladwin.  Furthermore, Lekson adds on top of this enormously difficult task the additional task of adding a parallel intellectual history of Southwestern archaeology.  And yet, like I say, he mostly succeeds in this near-impossible task.

How does he do it?  Partly by limiting his narrative to the highlights of both stories, which admittedly makes it seem a bit thin at times.  This is largely countered by his the very extensive notes, where he relegates most of the in-depth argumentation over scholarly minutiae that would get in the way of the overall story.  And when I say “extensive,” I mean it; this is a book with 250 pages of text followed by 100 pages of notes.  I haven’t read through all the notes in detail, but they’re a mix of perfunctory citations for statements in the text and really long and detailed discussions of various archaeological points of contention and Lekson’s positions on them.

Part of the reason for this shoving of so much into the notes is to make the text more accessible.  The book is aimed both at professional Southwestern archaeologists and at popular audiences, and this dual purpose sometimes leads to some tension but mostly works.  Lekson is a very good and engaging writer.  He has a very idiosyncratic style, which some may not find appealing, but I like it, and it definitely contrasts with the turgid prose that is more typical of archaeological publications.  The story he tells here will probably appeal to the two audiences somewhat differently; other archaeologists are likely to look through the text and notes for questionable statements to contest (and there are plenty), while lay readers are probably more likely to just take in the story without thinking too much about it.  Neither of these approaches is ideal, perhaps, but the book does adequately provide for both in an innovative way.

The structure of the book involves parallel stories: each chapter includes both one period in the history of Southwestern archaeology and one period in the actual history of the ancient Southwest as determined (primarily) by that archaeology.  Lekson tries to unify the two parts of each chapter with a common theme, which works better for some than for others but often seems a bit forced.  In general, the intellectual history portions of the chapters are a bit weaker than the archaeological portions, which makes sense since Lekson is an archaeologist rather than an intellectual historian.  Still, he does make a serious effort to evaluate the research of his predecessors and colleagues in the context of their times and the prevailing intellectual currents both within the discipline and within society as a whole.  This is more than most archaeologists are willing to attempt, and it helps put the archaeological data he uses to reconstruct the “history” of the prehistoric societies he discusses into its own appropriate context.

Building with Pro-Book Sign, Carrizozo, New Mexico

That “history” really is history, too.  This is a story focused on events, rather than adaptations, and part of the importance of Lekson’s discussion of the history of archaeology is to situate himself within that history and, in general, to distinguish what he’s doing here from what archaeologists typically do.  Basically, he’s seeking to write history rather than science, whereas most archaeological research in the US since the 1970s or s0, as he demonstrates, has sought to be science.  (Longtime readers will know that I have my own opinions on this question, and that they’re mostly in line with Lekson’s approach here.)  His version of “history” will probably seem a little over-simplistic to many actual historians, just as his account of the history of archaeology will doubtless seem simplistic to actual intellectual historians and historians of science, but for the general reader and for most Southwestern archaeologists the general point should come across loud and clear.

In general, Lekson gives the general outlines for the story of the ancient Southwest as he sees it, but he downplays some of his own more controversial ideas.  The Chaco Meridian is confined to the notes and occasional brief allusions in the text.  There are plenty of quibbles I have with some of his specific interpretations, especially about Chaco, but the overall picture he presents is probably broadly acceptable to a relatively large number of other archaeologists.  He definitely comes down on the side of hierarchy and extensive Mesoamerican influence, but local origin, for Chaco, which shouldn’t be a surprise for anyone who’s read any of his other recent Chaco stuff.  He also tries to tie everything together into a larger story, emphasizing the likely connections between developments at Chaco and among the Hohokam in Arizona, the Mimbres in southwestern New Mexico, and other Southwestern groups, as well as contemporaneous developments in Mexico and in the Mississippi Valley.  These broad-scale connections are controversial among archaeologists, but I think Lekson’s right on track in emphasizing them.

I’m not sure how well this book will work as an introduction to Southwestern archaeology for people who know literally nothing about it.  For those who know nothing about the ancient Southwest and have no intention of learning about it in great depth, this would be an entertaining and informative read.  Moving on from this to anything else written on the ancient Southwest (with the possible exception of some of Lekson’s other stuff) would be a pretty severe shock, however.  The difference in both tone and content is huge.  For people who are interested in the subject and have read one or two other books on it, however, this would be a very useful introduction to a very different way of thinking about these issues.  All professional Southwestern archaeologists should absolutely read it, not so much because they’ll learn much from it, although they might, but because it outlines a very different way of thinking and writing about the ancient Southwest that they should really be familiar with, even if they don’t want to do it themselves.

Personally, while I don’t agree with all of Lekson’s interpretations, I find this book inspiring.  Lekson is really pioneering a new way of writing the story of the ancient Southwest, and reading his version really makes me want to follow in his tracks and write my own version of the story, using his guidelines but reaching my own conclusions.  I don’t know if I’ll actually be able to follow through and write my own book, but it’s something I’ve been considering for a while now and reading Lekson’s attempt has made me more tempted than ever to actually do it.  After all, I’ve got plenty of time on my hands these days.

The Library Bar & Grill, Albuquerque, New Mexico

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An Interesting Macaw-Related Fact

Room 38, Pueblo Bonito

In a recent post, I noted the limited distribution of macaw remains within Pueblo Bonito.  While this site has a much higher number of macaws than any other Chacoan site, and more than almost every other site in the prehistoric Southwest, within the site macaw remains were highly concentrated.  All macaws were found in the eastern half of the site, and most were in the eastern part of “Old Bonito” at the northern end of the overall site, particularly in Room 38, which had twelve.  This suggests to me that macaws were closely associated with whatever social group lived in or used that part of Pueblo Bonito.

It’s hard to say what that social group was, but it’s possible that the burials in a complex of four rooms in the northern part of Old Bonito were associated with it.  Associating these burials with the eastern rooms in Old Bonito is perhaps a bit of a stretch, since the burial rooms are actually in the western half of the Old Bonito arc, but they’re just barely on the west side, and there is a separate set of burial rooms at the far western end of Old Bonito that could be plausibly associated with whatever social group lived in or used those rooms.  There is no equivalent set of burial rooms in the eastern part of the arc, although there are a few isolated burials of infants and fetuses.  (Two of the infant burials, in Rooms 306 and 309, were associated with macaws.)  The eastern end of Old Bonito was covered over by later construction and is poorly known, but there is no evidence that it ever held a mortuary complex comparable to the one at the western end.  Given the circumstances, I think it’s plausible that the northern burial complex was associated with the group (or one of the groups) associated with the eastern part of Pueblo Bonito, perhaps in addition to the group associated with the immediately adjacent room suite at the west end of the northern part of Old Bonito, if this was indeed a different group.

Western Burial Rooms in Old Bonito

Analysis of the Pueblo Bonito burials by Nancy Akins for the Chaco Project found that, judging from cranial attributes, the northern and western burial groups were distinct from each other but internally homogeneous.  This suggests that they probably represented kin-based social units, and that the site consisted of at least two of these units, perhaps occupying or using different areas.  Akins couldn’t find a very large sample of burials from other sites in the canyon for comparison, but she was able to compare burials from three small sites in the canyon.  One of these, Bc 59, is across from Bonito on the south side of the canyon near Casa Rinconada, while the other two, 29SJ299 and 29SJ1360, are in Fajada Gap, a few miles east and the location of a substantial community of small houses and two great houses (Una Vida and Kin Nahasbas) in close proximity to Fajada Butte.

While the two burial populations in Pueblo Bonito weren’t particularly similar to each other, they more closely resembled the small site samples.  Specifically, the western burial population was similar to the one from Bc 59, while the northern burial group was more similar to the Fajada Gap group.  Importantly, the two Bonito groups were both more similar to these small-house populations than they were to each other.  This suggests that kinship connections among different sites in the canyon were complicated and didn’t break down on straightforward great house v. small house lines.

Bc 59 from Casa Rinconada

What does all this have to do with macaws?  Well, there is only one small house site at Chaco (as far as I know) that has produced macaw remains, and that site is… 29SJ1360, one of the sites with burials that patterned with the northern burial group at Bonito!  As reported by Peter McKenna in his report on this site, which was excavated by the Chaco Project, a few macaw bones were found in the fill from one of the pit structures.  While there were only a few bones found, they were all unique, suggesting the presence of only one macaw, and from various parts of the body, suggesting that the whole macaw was present.  This fill was only casually screened for artifacts and was later used to backfill the pit structure, so the rest of the macaw is probably still there.  This site also had an unusual architectural feature, a small bin attached to the outside of one of the roomblocks, that according to McKenna looked “remarkably like a parrot bin.”  One important feature that appears to have led to this conclusion was the presence of an adobe “plug” in the north wall, presumably reminiscent of the stone plugs used with “cage stones” at macaw pens at Casas Grandes, where there is substantial evidence for the keeping and breeding of macaws a few hundred years later.

This is all pretty tentative, of course.  Very few sites at Chaco have been excavated, so we have very little sense of the overall distribution of rare finds such as macaw remains.  Still, two separate lines of evidence (biological relationship and association with macaws) seem to point to a strong connection between the northern/eastern part of Pueblo Bonito and at least some sites in the Fajada Gap community, which is not particularly close to Bonito.  Given the rarity of macaws, especially, this seems significant.

Fajada Butte with Green Vegetation

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Chaco before Chaco: The Basketmaker III Period

Basketmaker Pithouse, Mesa Verde

The Basketmaker III period (ca. AD 500 to 750) is a very important time for understanding the prehistoric Southwest.  Maize agriculture had been introduced earlier, although exactly how early is still a matter of debate, and it was definitely well-established by the immediately preceding Basketmaker II period, but Basketmaker III saw the introduction of beans, pottery, and the bow and arrow, all of which led to major changes in the lifestyles of local agriculturists.  Residence was in pithouses, which are clearly ancestral in form (and probably in function) to the “kivas” of later sites, and while these are usually found isolated or in very small groups, there are a few known examples of large “villages” containing dozens of pithouses.  The processes that led to the formation of these sites, as well as their relationships to the more common isolated sites, are very poorly understood, but it seems pretty clear that residential aggregation in certain locations during this period set the stage for the later formation of large villages during the succeeding Pueblo I period and afterward.

Two of the largest and best-known Basketmaker III villages are in Chaco Canyon.  The better-known of these, by far, is called Shabik’eschee Village, and it is located on the lowest terrace of a finger of Chacra Mesa at the east end of the current Chaco Culture National Historical Park.  Shabik’eschee was excavated by Frank H. H. Roberts in the 1920s as part of the Smithsonian/National Geographic project led by Neil Judd.  The main focus of the project was the excavation of Pueblo Bonito, but Judd had other members of the team, including Roberts, excavate several other sites in and around the canyon as well.  Roberts published his results in 1929, and this publication has been enormously influential in shaping subsequent interpretations of Basketmaker III villages and the period as a whole.

Looking South from Peñasco Blanco toward 29SJ423

The Chaco Project in the 1970s did some additional work at Shabik’eschee, as well as at the other Basketmaker Village in the canyon.  This site, known as 29SJ423, is just south of Peñasco Blanco at the far west end of the canyon, near the confluence of the Chaco and Escavada Washes.  It is situated in a similar location to Shabik’eschee, on a lower terrace of West Mesa (but above Peñasco Blanco, which is on the lowest terrace).  Tom Windes excavated a small portion of 29SJ423 in 1975, but he and other Chaco Project personnel soon came to the conclusion that additional excavation there would not be worth the considerable effort involved.  The collections from this excavation are important, however, since they were acquired using more careful, modern methods than Roberts’s.  Similarly, a very small amount of additional excavation at Shabik’eschee in 1973 has provided important supplemental information with which to evaluate Roberts’s interpretations.

Windes and Chip Wills published an article in 1989 looking back at Roberts’s interpretations at Shabik’eschee in the light of the additional knowledge gained by the Chaco Project excavations.  They concluded that some of Roberts’s ideas, such as his proposal that the site had two discrete periods of occupation separated by a hiatus during which it was abandoned, are likely untenable, and they also concluded that the site was considerably larger than Roberts thought.  They agreed with Roberts that some of the pithouses had been abandoned and their materials were used in subsequent construction, but they saw this as more of an ongoing process related to the short use-life of pithouses and the demands of demographic processes rather than a discrete series of two occupations.  They also saw more spatial patterning in the layout of pithouses within the site than Roberts did, suggesting that the pithouses grouped into what might be family residence units, although they were quite tentative in this finding and did not use these groups as units for any subsequent analysis.

Pinyon Trees, Pipe Spring National Monument

Wills and Windes also posited a novel interpretation for the site as a whole.  Rather than seeing it as a permanent agricultural village, they saw it as a site of occasional gatherings of more mobile families practicing a “mixed” subsistence strategy of small-scale agriculture along with hunting and gathering.  In their interpretation, a small number of families inhabited Shabik’eschee permanently, while others joined them periodically to take advantage of the site’s proximity to piñon woodlands in years with bountiful piñon-nut harvests.  They based this theory on the presence of two types of storage facilities at the site: household-level storage in the antechambers associated with some but not all of the pithouses (presumably the residences of permanent residents) and community-level storage bins scattered around the site.  The idea is that occasional surpluses of corn or whatever would be stored in the bins, and the people who lived at the site permanently watched over it and protected it.  Whenever there was a plentiful crop of piñon nuts, which happens at irregular intervals in the fall, people who lived the rest of the time in scattered locations throughout the area would congregate at Shabik’eschee to take advantage of this and stay for the winter.  If conditions in the spring were good for planting, people might stay longer and plant their crops in the area, but if not they would move on to more attractive planting locations.  Other pithouse villages, such as 29SJ423, would presumably have served similar purposes, allowing periodic aggregation to take advantage of various localized resources.

This is an interesting theory, but it’s based on exceptionally thin evidence.  Wills and Windes even concede that they are spinning this whole story purely from the nature of the storage facilities at the site, and they note that there are other ways to interpret the communal bins in particular.  Instead of protecting food stores during periods of reduced occupation, they may just have functioned to protect them in general.  The shape of the bins makes it more difficult to access their contents, which Wills and Windes interpret as evidence for a sort of semi-caching, but it would also just provide better protection from the elements, vermin, etc. for the contents.  Basically, there’s just no reason from the available evidence to buy the Wills and Windes theory.

"Pithouse Life" Sign at Mesa Verde

Indeed, the assumptions behind this theory seem problematic to me.  The ethnographic comparisons Wills and Windes use to support it are mostly from hunter-gatherer societies, and indeed their model seems to imply that the residents of Shabik’eschee were basically hunter-gatherers who did some farming on the side.  Such societies exist, and may well have existed at certain times in the ancient Southwest (such as the late Archaic), but recent studies have shown with increasing certainty that heavy dependence on agriculture was widespread already in the Basketmaker II period.  Wills and Windes seem to see the Basketmaker III inhabitants of the Chaco area as just beginning to experiment with adding agriculture to a hunter-gatherer lifeway, but it’s much more likely that they were full-time agriculturalists and had been for centuries.  They did of course still do some hunting and gathering, as their Pueblo descendants have continued to do up to the present day, but while this may in some sense qualify as a “mixed” economy that shouldn’t obscure the important fact that Pueblo societies have been overwhelmingly farming-based societies since well before the occupation of Shabik’eschee.

I think this interpretation, and others like it which were popular in Southwestern archaeology in the 1980s, results in part from the enormous influence of Lewis Binford on the development of processual archaeology.  Binford’s personal research and expertise were largely on hunter-gatherer societies, and the guidelines he set forth for “archaeology as anthropology” that were eagerly followed by young “New Archaeologists” were heavily influenced by that background.  Wills and Windes cite Binford several times in this article.

Excavating the Lift Station Site in the Chaco Maintenance Yard

Be that as it may, this is an important article just in providing an updated take on the facts about Shabik’eschee, which as Wills and Windes note has been very important in the interpretation of ancient societies generally.  It contains relatively little information about 29SJ423, but it does briefly discuss this site as a comparison.  It says even less about the much more numerous isolated Basketmaker III sites in the canyon, but it notes that Chaco Project surveys identified at least 163 pithouse sites from this period.  One that they didn’t find, because it was deeply buried under the ground, was later found by the park in the course of trying to build a lift station for the septic system.  This site, informally known as the Lift Station Site, is a Basketmaker III pithouse that was excavated while I was working at Chaco.  One of the more interesting things it revealed was an apparent location for pottery manufacture.

One of the major problems with trying to understand the Basketmaker III period at Chaco is precisely that the site are typically deeply buried, so it’s hard to even know how many of them there are.  It’s clear that this was a period of significant population in the canyon, but it’s hard to tell how many sites were occupied simultaneously.  This problem is exacerbated by the difficulty of dating many of the sites.  Tree-ring dates are often hard to obtain from the scarce wood found at excavated sites, and Shabik’eschee is particularly poorly dated.  The few tree-ring dates available seem to suggest it was occupied at some point after the mid-500s, but there are no cutting dates so any greater precision is impossible.  29SJ423 did produce two cutting dates, at 550 and 557, so it seems the two villages were most likely contemporaneous.  The isolated sites are even harder to date, of course, but the Lift Station Site produced corn that was radiocarbon dated.  I don’t know the dates that resulted, but I did hear that they were earlier than was expected based on the pottery types found.

Whole Pot from the Lift Station Site

The size of the Basketmaker III occupation at Chaco, and particularly the presence of the two large villages, has important implications for understanding the subsequent history of the canyon that I think are just beginning to be realized.  The local population seems to have declined during the subsequent Pueblo I period (ca. AD 750 to 900), when people seem to have begun to move in large numbers to higher elevations where they formed some really large villages.  However, it’s not clear that Chaco was completely abandoned during this period, and recent improvements in dating the early great houses in the canyon have shown that some of them, especially Pueblo Bonito, go back further than was once thought.  Pueblo Bonito is now known to have been begun no later than 860, and the earliest part of it may date much earlier, possibly to 800 or even before.  This means that the gap between the Basketmaker III villages and the earliest great houses suddenly looks a lot smaller, and may disappear entirely.  There are pithouses under the plaza at Pueblo Bonito that may date to very early Pueblo I or even Basketmaker III, and there is a small Pueblo I occupation at Shabik’eschee that dates as late as 750.  This suggests that these two iconic sites in Chacoan archaeology, generally interpreted in very different ways, may actually overlap in occupation.  This would require some serious modifications of the ways the origins of the Chaco system are often interpreted.

Chaco had been an important place for a very long time when it started to become a major regional center around AD 1040.  It’s looking increasingly plausible, though by no means certain, that it had been continuously occupied for 500 years at that point, and even if there was a brief gap between the Basketmaker III villages and the first Pueblo I great houses it is very unlikely that is was long enough for people to have forgotten about Chaco and what had happened there.  Even if many of the people who built and/or occupied the early great houses in the 800s hadn’t been born at Chaco, they probably knew it was there long before they made it their home.

Wills, W., & Windes, T. (1989). Evidence for Population Aggregation and Dispersal during the Basketmaker III Period in Chaco Canyon, New Mexico American Antiquity, 54 (2) DOI: 10.2307/281711

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How Old Is Pueblo Bonito?

Room 6, Pueblo Bonito

The “Chacoan era” is a period of about 100 years in the eleventh and early twelfth centuries AD during which Chaco Canyon was at the center of some sort of system that covered a large portion of the northern Southwest.  The exact nature and exact extent of that system are endlessly debated, but the period during which it existed is fairly well-established.  The exact dates given for the duration of the system vary among different researchers, and I’ve given various versions of them myself.  Probably the most common ending date is AD 1130, which coincides both with the approximate end of apparent construction in the canyon and the onset of a 50-year drought that is generally thought to have had something to do with the decline of Chaco.  To make it an even century, 1030 is a useful starting date for the Chacoan era, although it doesn’t actually correspond to anything special in the canyon as far as we can tell.  A better starting date might be 1040, which is approximately when the expansion of Pueblo Bonito began, or 1020, which is about when construction began at Pueblo Alto.  Using these starting dates with the hundred-year span gives ending dates of 1140 or 1120, which again are roughly equivalent to the end of major construction in the canyon.  (It’s a lot easier to date the beginnings of phenomena in the ancient Southwest than the ends of them, due largely to the reliance on tree-ring dates.)

Whenever we say the Chacoan era began, it was long after the first great houses in Chaco Canyon were built.  Indeed, the canyon had a long and probably very eventful history well before things really got going in the early 1000s.  During the 900s it may not yet have been important on as large a scale as it became later but it was definitely already a place where things were happening.  The origins of Chaco lie even earlier, however.

Type I and Type II Masonry Abutting at Peñasco Blanco

The first three great houses built in the canyon were Pueblo Bonito, Una Vida, and Peñasco Blanco.  Una Vida is mostly unexcavated and Peñasco Blanco is completely so, so the dating of them relies mainly on tree-ring sampling of exposed wood.  This has shown that these two sites probably date originally to the late 800s, with extensive expansion in the 900s.  The earliest cutting date at Una Vida is from AD 861, while Peñasco Blanco has a cluster of cutting dates at AD 898.  Both have clusters of dates in the 900s that suggest that much of the early construction dates to this period, and both also show expansion later, during the Chacoan era itself.  Beyond that, though, not much can be said about the chronology of these sites.

Pueblo Bonito is a different story.  It’s almost completely excavated, and while the excavation took place a long time ago, it left a lot more exposed wood than at most other sites.  The recent Chaco Wood Project, which sought to sample every piece of exposed wood in the canyon to develop as full a chronology as possible, had its most spectacular results at Bonito.  These were reported in part in an article in 1996 by Tom Windes and Dabney Ford, and the implications of the new dates for the architectural history of the site were more fully explained by Windes in a subsequent book chapter published in 2003.

Beams Sampled for Tree-Ring Dating in Room 227, Pueblo Bonito

To get a sense of the scale of this project, before it began in 1985 there were 163 pieces of wood from Pueblo Bonito that had been tree-ring dated.  By the time the 1996 Windes and Ford article was published, this figure had risen to 4,294.  That’s a big difference!  We now have a much better idea of when different parts of Bonito were constructed, and that has shed important light on developments in the canyon at large and their relationship to events elsewhere in the Southwest.

Before this project, Pueblo Bonito was thought to have been initially constructed in the early 900s, with some reuse of beams from earlier structures accounting for a handful of dates in the 800s.  This interpretation, expressed most influentially by Steve Lekson in his 1986 book on Chacoan architecture, was based largely on a tight cluster of cutting dates at AD 919 from Room 320 in the western part of “Old Bonito.”  The enlarged sample, however, showed that it was actually this cluster that was a fluke, and that other beams from this wing produced dates in the mid-800s that more likely represent the initial construction of this part of the site.  This seems particularly likely because the types of wood represented by these beams are largely piñon, juniper, and cottonwood, locally available species that were widely used early on, before the beginning of large-scale, long-distance procurement of large beams of ponderosa pine and other high-elevation woods.  This suggests that the beams in Room 320 which dated to 919 were probably replacement beams rather than original construction.  This block of rooms at the western end of Old Bonito was probably built around 860.

Room 320, Pueblo Bonito

Lekson thought this roomblock was probably the earliest part of the site.  As it turns out, it was even older than he thought, but evidence from other parts of Old Bonito suggests that it was not actually the earliest part.  A cluster of cutting dates at AD 891 in the northeast part of Old Bonito, which was clearly added onto the north-central part to the west of it, suggests that it was the north-central part that was actually first.  This makes sense just from looking at the plan of the rooms, actually.  This part of the site is less regular and formal in organization than the east and west wings of Old Bonito, and since it lies between them it seems logical that they would have been added on to the original central room suites.  This is a bit hard to interpret, however, since the places where these different parts of the Old Bonito arc would have come together are mostly buried under complicated later construction.

Windes suggests in his 2003 paper that the very oldest part of the site was the block consisting of Rooms 1, 2, 4/5, 6, 35, 36, 37, and 61.  None of these rooms produced wood that could be dated.  Room 6 contains a considerable amount of original wood, which can be seen today under a modern roof put on to protect it, but this is mostly cottonwood, which is very difficult to date.  As noted above, however, the use of local types of wood like cottonwood is a characteristic of very early construction at Chaco, so even though these beams couldn’t be dated they do still provide some evidence that this part of the site is very early.  The western roomblock, dating to around 860, was probably added onto this one.  This implies that the north-central block predates 860, and Windes says it is “probably much earlier” even than that (although he doesn’t explain why he thinks this).

Intact Roof Beams in Room 6, Pueblo Bonito

How much earlier?  It’s hard to say.  The earliest cutting date at Bonito is 828, from Room 317 in the western roomblock, which both Lekson in 1986 and Windes and Ford ten years later considered likely to be a reused beam.  Since the overall distribution of dates in this block suggests construction around 860, this is probably right, and it’s hard to say where the beam would have come from.  Probably not the north-central roomblock, which would probably have still been in use in 860.  Interestingly, this beam is of ponderosa pine.

The north-central roomblock could well date to around 800 or even earlier, and that brings us to an interesting point.  There are a bunch of pitstructures buried deep under later construction in what would have been the original plaza of Old Bonito; these were not extensively excavated, but they probably correspond to the room suites that make up Old Bonito and therefore date to the 800s.  There are two even earlier pitstructures, however, further south in the later plaza of the expanded Bonito.  Neil Judd, who excavated the site in the 1920s, didn’t pay much attention to them because he thought they were too early to have anything to do with Pueblo Bonito itself.  They apparently date to the Pueblo I or late Basketmaker III period.  Back when the consensus was the Bonito itself wasn’t built until 919, it made sense to agree with Judd that these pithouses were too early, but now that we know that the earliest parts of Old Bonito date well back into Pueblo I it starts to look more plausible that there is actually some continuity here.  Since Judd didn’t look very closely at the early pithouses, we have no way of dating them, which is unfortunate, but one possibility that is looking increasingly plausible is that there was no hiatus at all between the occupation of those pithouses and the earliest occupation of Old Bonito.  In that case, Pueblo Bonito as an important, inhabited location (rather than as the building we see today) might actually date back to Basketmaker III.  And, importantly, whoever lived there at that time wouldn’t have been alone in the canyon.  But that’s an issue for another post.

Windes, T., & Ford, D. (1996). The Chaco Wood Project: The Chronometric Reappraisal of Pueblo Bonito American Antiquity, 61 (2) DOI: 10.2307/282427

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Warren K. Moorehead, Cartoon Villain

Aztec West Great House, Aztec Ruins National Monument

In the spring of 1892, an expedition headed by Warren K. Moorehead traveled through northwestern New Mexico to collect archaeological specimens for the Chicago World’s Fair to be held the next year.  Moorehead was a young man from Ohio who had already conducted considerable excavations there that had drawn the attention of Frederic Ward Putnam of the Harvard Peabody Museum.  Putnam hired Moorehead to collect artifacts in Ohio and elsewhere for the World’s Fair.  Moorehead’s Ohio work was important to the definition of the Hopewell Culture and the acquisition of the Fort Ancient site by the Ohio Historical Society, and by the time of his death in 1939 Moorehead was considered one of the preeminent American archaeologists.  He wrote up some of his observations from the 1892 New Mexico expedition in an article published in 1908 which contains some important early information about the archaeological remains along the Animas and La Plata Rivers before those areas were extensively developed.

Moorehead’s party surveyed the major ruins at Aztec, but John Koontz, who owned the site at the time, would not let them excavate there.  (This is an issue that would recur in Moorehead’s Southwestern adventures.)  The 1908 article contains a decent description and plan of the West Ruin at Aztec, including the observation of an obvious road leading to a nearby quarry site that was the apparent source of building stone.  The more important part of the article, however, deals with the La Plata, where the group spent more time and were apparently given permission to excavate several sites.  Moorehead noted very extensive irrigation systems along the valley bottom, which he suggested accounted for the numerous prehistoric sites and the apparently very large population they indicated.  Since the La Plata Valley has been extensively developed for modern agriculture since Moorehead’s time, these observations are very useful for understanding the perennially understudied archaeology of that area.  It’s not totally clear how many sites the group excavated, but Moorehead describes one burial with numerous associated pots and mentions a large, three-story site surrounded by many smaller sites.  This is probably the community now known as the “Holmes Group,” after William Henry Holmes, another early archaeologist who studied them.  Moorehead estimated about two hundred rooms in the community, half of them in the great house.

The Moorehead party excavated many graves and collected the pottery left with them, but Moorehead says that the bones themselves “were in such a state of decay that it was not possible to preserve them.”  The group also found an interesting vertical masonry shaft, fourteen inches square and eight feet, five inches deep.  The bottom of the shaft was paved with slabs and connected to a horizontal passage leading north, which Moorehead’s group excavated for about four feet before they “were compelled, unfortunately, to abandon the work; and thus were prevented from gaining sufficient evidence to determine the purpose of the structure.”  Moorehead doesn’t explain what compelled this stop to the digging.  He does speculate about the possible purpose of this shaft:

It could not have been a chimney, for neither the stones nor the logs showed signs of smoke or heat, although fragments of charcoal were found occasionally during the excavation; nor is it likely that the shaft was used as an air flue for the purpose of ventilation, both on account of the narrowness of the perpendicular portion (fourteen inches), and the apparent disregard manifested by the ancient Southwestern villagers of everything that might tend to promote hygienic conditions.

Zing!  In fact, this shaft almost certainly was a ventilation shaft associated with a kiva, similar to those documented by Jesse Walter Fewkes at Mesa Verde.  The fact that it led north is a clear indication, and Moorehead’s objection on the basis of size doesn’t make a whole lot of sense.  His snide comment about hygiene is odd, though perhaps indicative of the gentlemanly racism common among early anthropologists, and it would perhaps be unfair to tar Moorehead too much with it, as he actually was quite concerned with the fair treatment of Indians and worked hard throughout his life to advocate for their interests in a rather paternalistic way, which was not a common thing for archaeologists to do.  Still, he was a man of his times, and he was apparently unimpressed with the sanitary conditions of the modern Pueblos.

Opening of Vent Shaft to Kiva L, Pueblo Bonito

Moorehead’s attitudes may have been slightly more progressive than those of his archaeological contemporaries, but his methods weren’t.  His style of archaeology was very heavily based on recovering artifacts for his various patrons, first Putnam and later Robert Peabody, who made him head of the Robert S. Peabody Museum of Anthropology at Phillips Andover.  As shown by his 1908 article, he did do some documentation of the sites he investigated, but the focus was always on the artifacts rather than the sites.  The Ohio History Society’s short biography of him notes, rather defensively, that this was not uncommon at the time:

Moorehead sometimes is remembered unkindly for his supposedly crude excavation methods and for his involvement in the buying and selling of artifacts. Both criticisms are unfair. In the light of today’s standards his field methods certainly would be considered deficient, but for their time they were not all that unusual. The practice of buying and selling artifacts, particularly specimens considered to be duplicates, also was not unprecedented at the time.

This is true, but it’s not so much a defensive of Moorehead as an indictment of archaeology as a discipline at the time.  The contrast with Richard Wetherill and George Pepper’s excavations at Chaco in the 1890s is instructive.  Their methods are often defended along the same lines, but in fact compared to the likes of Moorehead they did a very good job of documenting their work.  Pepper’s site report on Pueblo Bonito, though based on his sometimes sketchy field notes and quite inadequate by modern standards, is a wonder of careful documentation of artifact contexts and room features compared to Moorehead’s typical work.  Furthermore, Wetherill was a skilled amateur photographer at a time when that was rare, and there are numerous photographs of the excavations at Bonito.  I don’t know of any other excavation projects in the 1890s that were photographed as systematically as those at Bonito.  Moorehead never took any pictures of his work as far as I know.

South Wall of Room 53, Pueblo Bonito

Indeed, we can compare Wetherill and Pepper’s methods directly with Moorehead’s, because Moorehead excavated at Pueblo Bonito too.  In 1897, Moorehead made another collecting expedition to the Southwest, this time on behalf of Peabody, and one of the stops he made was at Chaco Canyon.  Wetherill and Pepper had begun excavations at Pueblo Bonito in 1896, sponsored by none other than Frederic Ward Putnam, who was at this point affiliated with the American Museum of Natural History, and word of their spectacular finds such as the burials in Room 33 had probably gotten out.  In any case, Moorehead showed up at Chaco in the winter, the offseason for the AMNH party, and proceeded to tear the hell out of two rooms just north of Room 33.  These rooms, which Pepper would later designate Rooms 53 and 56, were apparently part of the same burial complex as Room 33, and they contained numerous burials and grave goods.  The grave assemblages were apparently not as elaborate as those in Room 33, however, and Moorehead was not particularly impressed with what he found (which is perhaps why he didn’t continue to excavate).  He did find one complete skeleton, wrapped in a feather robe, which he thought was of a young woman.  Nancy Akins, who reexamined the remains from Pueblo Bonito for the Chaco Project, concluded that this burial was actually of a man aged 40 to 44.  She also noted four skulls, now in the Field Museum, which were also probably from these rooms.  The Moorehead group didn’t fully excavate the rooms, and when Wetherill and Pepper returned in the summer they excavated what was left and sorted through the mess left by Moorehead, who had apparently thrown the fill from the rooms around haphazardly.  They found a few more artifacts and burials, but couldn’t say much about the original state of the rooms beyond noting two subfloor graves in Room 56 that Moorehead had opened.

Here’s what Akins had to say about Moorehead’s work in Rooms 53 and 56:

It is unfortunate that Moorehead plundered these two rooms. There are indications that a fair number of persons were buried in them. It is unlikely that they contained the amount of ornamentation found in Room 33, as none is mentioned by Moorehead in his report, little is listed in the Phillips-Andover catalog, and Moorehead stated that no remarkable
discoveries were made.

Moorehead did write an account of this expedition, which was published by Phillips Andover and is not easy to find.  I haven’t been able to read it, but judging from his 1908 article on the other expedition and Akins’s comments I don’t expect that it contained much detailed information on his work at Pueblo Bonito.

South Wall of Room 53 from Room 56, Pueblo Bonito

Also on this trip, Moorehead stopped by Salmon Ruin, where the landowner, George Salmon, only allowed him to dig for three days.  This frustrated Moorehead, and it indicates that Salmon, like John Koontz, was concerned with preserving his ruin and not letting archaeologists like Moorehead tear it apart wholesale looking for artifacts.  Obviously Salmon was a bit more accommodating than Koontz, who apparently didn’t let Moorehead dig at all at Aztec.

In the context of Chaco, and especially in comparison to Wetherill and Pepper, Moorehead looks pretty bad, but it’s worth emphasizing that he really wasn’t that unusual at the time.  The line between pothunter and archaeologist was really quite thin, and many archaeologists of Moorehead’s generation started out digging haphazardly for artifacts and later transitioned to more carefully documented digging for information.  Earl Morris is a good example of a pothunter who successfully turned himself into a serious archaeologist, and Richard Wetherill is an example of a sort of semi-pothunter who tried to make that transition but failed.  Moorehead’s background was similar, and he was more successful in ingratiating himself with the emerging academic archaeological establishment than Wetherill but probably less successful than Morris.  Part of the issue was just the change in archaeological practice over time; Wetherill died in 1910 (101 years ago today), whereas Moorehead lived until 1939 and Morris, who was of a younger generation, lived until 1956.

Interpretive Plaque at Wetherill Cemetery

Wetherill often gets cast as a villain in the story of Southwestern archaeology.  This is largely the doing of Edgar Hewett, who was an inveterate opponent of what Wetherill and Pepper were doing at Pueblo Bonito, which he characterized as large-scale looting.  Hewett’s line was eagerly adopted by the Santa Fe press, and it has become entrenched in popular understanding and even implicitly adopted by many archaeologists today.  It’s important to note, however, what Hewett was actually objecting to.  The biggest problem as he saw it was not that artifacts were being taken out of Pueblo Bonito but that they were being taken to New York, to sit in the AMNH (where most of them remain to this day).  Hewett wanted artifacts from Chaco not to stay at Chaco, but instead to be brought to Santa Fe and kept at his own institution, the Museum of New Mexico.  His characterizations of Wetherill and Pepper’s activities tended to carefully omit the involvement of the AMNH, which helped to drum up support for his cause among locals outraged by outsiders coming in and taking away artifacts.  Hewett eventually got his wish, and in the 1930s and 1940s he dominated archaeology at Chaco and throughout New Mexico.

Hewett’s success in tarring Wetherill as a pothunter shouldn’t blind us to the realities of the context Wetherill and Pepper were working in.  Their methods were crude compared to today’s, but within the range of variation in methods at the time they really were quite good, and much better than Moorehead’s crude methods.  Indeed, in some respects they were significantly better than the methods employed in Hewett’s own excavations at Chaco thirty years later.  The dispute between Hewett and Wetherill wasn’t about methods, and it wasn’t about “professional archaeologists” versus “amateur pothunters.”  Rather, it was a dispute between two groups of professional archaeologists and their institutional sponsors over who should be excavating at one of the most important archaeological sites in the region and which museum should get the artifacts they found.

Moorehead’s bit part in this drama really just serves as context, I think.  Despite the title of this post, I don’t think it’s really reasonable to cast him rather than Wetherill as the villain of the story.  Instead, Moorehead just illustrates that there was more to archaeology in the 1890s than Wetherill and Hewett, and that it is best to interpret the history of research at Chaco within that broader context.

Moorehead, W. (1908). Ruins at Aztec and on the Rio La Plata, New Mexico American Anthropologist, 10 (2), 255-263 DOI: 10.1525/aa.1908.10.2.02a00080

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