Archive for the ‘Built Environment’ Category


Entrance Sign at Hovenweep National Monument

Today is the winter solstice, which also makes it the eighth anniversary of this blog. I like to mark these astronomical occasions with posts about archaeoastronomy, which is one of the most interesting fields of study relating to Chaco Canyon and other prehistoric sites of the Southwest. Today I just have a brief and fairly speculative post connecting some other suggestions I’ve made about how astronomy related to the larger cultural systems of these societies.

In Ray Williamson’s book Living the Sky: The Cosmos of the American Indian, which as I’ve noted is still a very good introduction to the subject despite being more than 30 years old now, he opens the chapter on the ancient Pueblos with fieldwork he had personally done at Hovenweep National Monument. Hovenweep is one of the more obscure Park Service units in the Southwest, consisting of several different clusters of ruins scattered on both sides of the Colorado-Utah state line just north of the Four Corners. The sites themselves are quite impressive, however, and well worth visiting. The most prominent and striking are the “towers” that tend to be placed along the edges of canyons near their heads, which are generally quite well preserved. These have not been extensively studied by archaeologists, and this area is not very well understood compared to many other parts of the Colorado Plateau


Hovenweep Castle

From what little we do know, the towers and related sites seem to be post-Chaco in age, and they don’t show much evidence of Chacoan influence. Williamson mentions tree-ring dates at Hovenweep Castle, the largest tower site in the Little Ruin Canyon/Square Tower group near the monument’s visitor center, of AD 1166 and 1277, which is after the main florescence of Chaco and contemporary with the cliff dwellings at Mesa Verde. The towers do have some architectural similarities to the cliff dwellings, and overall seem to fit into the Mesa Verde or Northern San Juan tradition. They don’t show any particular resemblance to Chacoan “great houses” in either size or form.

Williamson measured potential alignments to the solstices and equinoxes at Hovenweep Castle and a smaller site nearby called Unit Type House, as well as at another group of sites within the monument. These alignments generally involved small “ports” or holes in the exterior walls through which sunlight shines on or near the days in question. The beams coming through these ports tend to fall on opposite corners, suggesting that they were being used as calendars to track the progress of the sun, presumably to schedule rituals and/or agricultural activities. There is ample evidence in the modern ethnographic record that the modern Pueblo “Sun Priests” and other officials used solar observations similarly.


Unit Type House, Hovenweep

What I want to note here, however, is that Williamson found ports with solar alignments both at Hovenweep Castle, the largest site in the Little Ruin Canyon group and plausibly either a public/ritual facility or the residence of a community leader (or both), and at Unit Type House, which in keeping with its prosaic name is a smaller site that was likely a more mundane residence. This suggests that watching the sun and keeping calendars was a practice not limited to chiefs or priests at Hovenweep, but was practiced by ordinary people as well. But why?

A possible answer comes from Frank Cushing’s pioneering ethnographic work at Zuni in the late nineteenth century, which is quoted by Williamson in this connection. According to Cushing, while the Sun Priest was responsible for the official observation of the sun to set the ceremonial calendar,

many are the houses in Zuni with scores on their walls or ancient plates imbedded therein, while opposite, a convenient window or small port-hole lets in the light of the rising sun, which shines but two mornings in the three hundred and sixty five in the same place.

Cushing implies that the reason so many people had their own calendars like this was to check the accuracy of the Sun Priest’s observations, which implies that the people didn’t necessarily trust him to get it right.


Plaque at Fajada Butte View Describing the “Sun Dagger” Petroglyph

So far, so good, and in keeping with the general tendency toward egalitarian ideology and mistrust of hierarchical authority for which the modern Pueblos are known. But what I find interesting is the contrast here with Chaco, where many astronomical alignments are known for the great houses and other sites that were potentially ritually important (like the “Sun Dagger” petroglyph atop Fajada Butte), but none as far as I know in the small houses where most of the population would have lived. Did the Chacoans trust their sun priests more than the later people of Hovenweep and Zuni?

I think they just might have, and this brings me back to another theory I’ve proposed: that the rise of Chaco to a position of regional dominance in the tenth and eleventh centuries AD may have been associated with Chacoan elites’ control of new and ritually important astronomical practices. The astronomical alignments at Chaco appear to be the earliest known ones in at least the northern Southwest, and possibly the Southwest as a whole, and it’s possible that the development (or acquisition) of observation techniques that allowed Chaco’s leaders to demonstrate unprecedented powers of prediction fueled their rise. As long as those powers seemed to hold, they may have been able to keep close control over knowledge of their techniques, or the common people may simply have not thought to question them.

But Hovenweep, with its apparently more “democratic” distribution of astronomical knowledge, dates to only slightly later than Chaco. So what happened in between?


Small House across from Pueblo Bonito

It’s hard to say, and this is one of the enduring mysteries of Chaco, but this period (roughly the middle decades of the twelfth century) does appear to have been a time of great change throughout the northern Southwest, with the ultimate result being the loss of Chaco’s regional influence, although the canyon itself wasn’t completely abandoned until the whole region was at the end of the thirteenth century. There were some major droughts that occurred during this period, which seem to coincide with some of the cultural changes, so maybe the Chacoan elites’ esoteric calendrical knowledge no longer seemed to have the control over rain and fertility that they had claimed, and people began to trust them less and to try to do their own observations too. Or maybe there was a more general spread of astronomical knowledge that undermined Chaco’s influence even if its power didn’t appear to fail. It’s very hard to tell exactly what happened, but the patterns are intriguing.

Anyway, that’s my solstice/anniversary post for this year. Thanks to my long-time readers for sticking with me all these years.


Winter Solstice Sunset

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Explanatory Plaque at Sun Temple, Mesa Verde

Today is the summer solstice, on which I like to do posts about archaeoastronomy. Today I’d like to discuss a well-known site, Sun Temple at Mesa Verde, which as its name suggests has long been associated with astronomical observations. As we’ll see, however, it appears that some of the early interpretations of the site’s architecture haven’t held up under further examination. This is another good example (along with Wupatki) of the need to carefully analyze proposed archaeoastronomical alignments.

Like many sites at Mesa Verde, Sun Temple was excavated and partly reconstructed in the early twentieth century by the pioneering archaeologist Jesse Walter Fewkes. Fewkes named the site “Sun Temple” after finding a feature that he interpreted as a “sun shrine” aligned to the position of sunset on the fall equinox. After identifying this possible alignment, Fewkes looked at the orientation of the building to see if there were any other astronomical alignments present. Sun Temple is D-shaped, with the flat side of the “D” to the south (a shape and orientation that those familiar with Chaco may find familiar), so the straight front wall was an obvious place to check for alignments. Fewkes, presumably guided by the equinoctial alignment of the shrine, initially checked to see if the front wall aligned to the positions of sunrise/sunset on the equinoxes, which would be the same and would mean the wall was oriented due east-west. He found that it was not, but was rather aligned about 20 degrees north of due east at the east end, and 20 degrees south at the west end.


Sun Temple, Mesa Verde

In his published reports Fewkes went on to conclude from this alignment that the front wall was actually oriented to the summer solstice sunrise. This is an important event in modern Pueblo societies, and subsequent research has found evidence for alignments to it in prehistoric Pueblo sites as well, so on first glance this seems like a reasonable conclusion. When archaeoastronomer Jonathan Reyman began to research the site using modern techniques in the 1970s, however, he found that it didn’t hold up, and published a short article explaining why.

The basic gist of Reyman’s article is very simple: The front wall of Sun Temple is indeed oriented to about 20 degrees north of east, but this is not the same alignment as the summer solstice sunrise at this latitude, which is more like 30 degrees north of east. Fewkes appears to have simply made a simple mistake. It’s not clear exactly how this would have happened, but Reyman suggests he either made a mistake in his notes or his notes were unclear and he became confused when writing them up for publication. In any case, this is a pretty clear-cut case of a mistake in the literature being corrected, and Fewkes’s error does not seem to have been propagated since. (Note that the NPS link I gave above says nothing about a solstice alignment.)

Reyman did also confirm that the “sun shrine” is aligned to the equinoctial sunsets and may well have been used to observe them, so the name “Sun Temple” remains appropriate (or as appropriate as it ever was). This is an intriguing building for a lot of reasons, some of which do support the idea that it had an astronomical function, but that’s a discussion for later. Sun Temple is also one of the most accessible sites at Mesa Verde, being on a mesa top where it can be visited without a guided tour, and it is well worth visiting even though it’s quite different from the cliff dwellings for which the park is best known.
Reyman JE (1977). Solstice Misalignment at Sun Temple: Correcting Fewkes The Kiva, 42, 281-284

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Chaco Petroglyph Panel Showing Abstract “Blanket” Designs

Chapter 11 of Crucible of Pueblos, by Rich Wilshusen, Scott Ortman, and Ann Phillips, is called “Processions, Leaders, and Gathering Places,” but I think a more concise description of its main concern is ideology. Specifically, this chapter looks at changes in the ideology of leadership, power, and community organization during the Basketmaker III and Pueblo I periods, as seen through the archaeology of public architecture, the portrayal of processions in rock art, and the reconstruction of related vocabulary through comparative linguistics. Due to this innovative interdisciplinary approach, I found this one of the most interesting chapters in the book. Some of the argumentation and conclusions strike me as either weak or overly speculative, but overall this is a fascinating example of how approaches from very different disciplines can be skillfully combined to produce a more complete picture of the past.

The overall argument in the chapter is fairly straightforward. The authors argue that there were a series of shifts in Pueblo society from the Basketmaker III to Pueblo I periods:

  • The overall settlement pattern shifted from dispersed hamlets to aggregated villages.
  • The locations for occasional ritual gatherings shifted from symbolically important central locations with public architecture to specific locations within villages that in some cases were likely residences of village leaders who exerted control over rituals they hosted.
  • The social ties that sustained communities shifted from personal relationships between individuals to symbolic relationships between abstract corporate entities to which individuals belonged.

The authors see all of these shifts as being ultimately driven by the rapid increase in population from an intensification of agriculture (the so-called “Neolithic Demographic Transition”). The actual evidence for this transition, and its relationship to agriculture, seems a bit thin to me, but at least on a theoretical level it makes sense, and there’s certainly no question that populations were increasing rapidly in the Mesa Verde region (to which this chapter, like several others, essentially confines itself due to the scarcity of comparable data for other areas) during the period they discuss.

From archaeology, the most important shift the authors discuss is the well-known change from dispersed settlements during Basketmaker III to aggregated villages in Pueblo I. (Again, we’re essentially just looking at the greater Mesa Verde area here, without any discussion of the possible Basketmaker III villages at Chaco Canyon.) One aspect of the Basketmaker III settlement pattern that is particularly important is the presence of “isolated” public architecture of presumed ritual function, which in some cases took the form of “great kivas” and in other cases took the form of “dance circles,” the main distinction being whether the structure appears to have had a roof. These structures are generally thought to have hosted occasional rituals that brought in people from throughout the surrounding area and helped to integrate them as a social “community.” In addition to the actual rituals performed, about which we know little to nothing, these events would have provided opportunities to trade, share information, and find marriage partners, all important activities to ensuring the success of the community and its members.

As people began to gather in aggregated villages during the Pueblo I period, the nature of public architecture begins to change. Great kivas are still being used in some villages, but less and less over time, and some villages don’t have them at all. Instead, it appears that some of the integrative functions of the great kivas are being taken over by U-shaped roomblocks with associated “oversized pit structures” that have features suggesting ritual use but, importantly, not in the same way as great kivas. The U-shaped roomblocks appear to have been at least partly residential in function, and they may have served as the residences of emerging village leaders who used the plazas they partly enclosed, as well as the oversized pit structures, to host community rituals that served many of the same functions previously served by great kivas. Unlike the great kivas, however, which appear to have been communal sites not associated with any particular members of the community, these structures would have been under the direct control of the families or kin-groups that owned them, who would therefore have the opportunity to amass ever more status, power, and wealth. There have been suggestions, repeated here, that these structures were the forerunners of the later “great houses” at Chaco and its outlier communities, which seems increasingly plausible as more is known about them. (It’s worth noting, however, that great kivas reappear at Chaco as well.)

So far so good, and this is about as far as the archaeology can take us. These ideas are plausible, but they’re not new. Where this chapter goes further than others, however, is in incorporating evidence from rock art as well. The specific focus is on rock art depicting what appear to be ritual processions. The authors analyze two specific panels in detail. One, from Comb Ridge in southern Utah, is thought to date to the Basketmaker III period and to depict the sort of gathering of dispersed communities at a central ritual site that was argued above to have been typical of this period. The other panel is from near Waterflow in northwestern New Mexico, and it is argued to date to later, after the collapse of the Pueblo I villages in the Central Mesa Verde region but before the rise of Chaco to the south. This site is at a key point along what may have been one of the main routes between those two areas, which may be important.

I won’t go into much detail about the analyses of the two panels, interesting though they are. The main points are that the Comb Ridge appears to depict at least two groups approaching a round great kiva or dance circle site from different directions, possibly reflecting the joining of two previously separate communities into one. The focus is on long lines of human figures, some of which have elaborate regalia or carry possible ritual objects, which may indicate that they represent specific individuals. Referring to an earlier study, the authors suggest that the focus on these rituals in Basketmaker III rock art represents a shift in ideology from earlier Basketmaker II art that focused on life-cycle rituals and individualistic shamanism to a more communal type of ritual associated with the central sites.

There is very little rock art associated with the Pueblo I villages, and no known procession scenes at all. The authors don’t discuss this fact in any detail, but it seems significant as evidence for a shift in ideology associated with the new ritual forms they describe as indicated by the architecture. Yet another shift appears to be indicated by the reappearance of procession scenes during the Pueblo I/Pueblo II transition as represented by the Waterflow panel. Here, the procession is primarily of animals rather than people, and they are approaching a square divided into halves and decorated with abstract designs. The whole panel has much more of an abstract feel, and it includes symbols of authority known from later Pueblo religion such as twin mountain lions who appear to be guarding the square. The authors interpret the square as representing the community, with the animals approaching it possibly being symbols of corporate groups like clans that make it up rather than known individuals. Of particular interest, the authors suggest on the basis of other rock art evidence that the symbols on the square actually represent a specific community, as there are apparently other symbols like this with various abstract symbols that may depict community in a sort of “heraldry” comparable to the city glyphs known from Mesoamerica. There are also intriguing petroglyphs of human figures with these squares as heads, possibly indicating village “heads” or chiefs. This system doesn’t appear to continue into later periods, at least in this form, though it may be worth taking another look at distinctive rock art motifs found at later sites to see if there is any continuity in the symbolism. The so-called “blanket” motifs found in rock art at Chaco are similar at least in form.

So the overall picture from the rock art evidence is of a shift from showing communities as consisting of groups of individual people who gather at a central location on certain occasions to more abstract depictions of communities as consisting of social categories, rather than individuals. This may reflect a further step in the development of community ideology after the first, apparently failed, experiments with village living during Pueblo I. The elaborate system that developed subsequently at Chaco may have been yet another step.

Turning to language, this is a particularly interesting part of the chapter for me given my linguistic background. It is based on Ortman’s dissertation, subsequently turned into a book, which considered linguistics along with other lines of evidence to understand the cultural makeup of the Mesa Verde region in the later Pueblo III period. While several languages from different families are spoken by the modern Pueblos, here the discussion is limited to the Kiowa-Tanoan language family, the only family that is both primarily spoken by Puebloan peoples and complex enough in structure to analyze historically in any detail. The analysis is based on what terms for culturally important items and technologies can be reconstructed to different stages of the language, and how the presence or absence of certain terms relates to when they were introduced in the archaeological record. So, for example, the (Puebloan) Tanoan languages share some terms related to agriculture with the (non-Puebloan) Kiowa language, but lack shared terms for such items as pottery, beans, and the bow and arrow. Since these items were introduced to the northern Southwest in the Basketmaker III period, it appears that Kiowa broke off from the other languages no later than Basketmaker II. The subsequent divisions within Tanoan look a lot shakier to me, but if they do hold up they seem to indicate that the Towa language split off during Basketmaker III, which would have left the language ancestral to Tiwa and Tewa as having been spoken during Pueblo I, possibly in some of the early villages of the Mesa Verde region. Tiwa and Tewa are said to have split after Pueblo I, which the authors of this chapter suggest indicates that it was the collapse of those villages that caused the split.

This is an interesting approach to trying to align the linguistic and archaeological records, and I’m glad people are looking at it. It doesn’t seem to add much to the other two lines of evidence in this specific case, however, and there are some potential issues that make it hard to apply in general. For one, it can be hard to tell if the inability to reconstruct a term to a given protolanguage truly indicates that the item it represents was not present during the period when that protolanguage was spoken, especially in a small language like Kiowa-Tanoan. Terms can be lost in daughter languages in many ways, with the ultimate result being the same in the present language as if it had never existed. However, this is a much more productive approach to the problem of correlating linguistics with archaeology than some others that have been tried, like glottochronology, and it’s definitely worth pursuing to see what insights it can provide.

Another problem, however, is that there are several other Pueblo languages not related to Kiowa-Tanoan, and this type of analysis doesn’t, and can’t, say anything about when and where they might have been spoken. A better approach to try to address the diversity of languages among the Pueblos is to look at loanwords, both between different Pueblo languages and between them and non-Pueblo ones, and try to see what can be inferred about when certain items were introduced to speakers of a given language based on that. There have been some studies along these lines that have given some interesting insights and more work would be useful.

Overall, this chapter is a really interesting approach to trying to correlate different types of analyses to complement each other and get a better answer to a specific question about the past than any one type of analysis individually. At the end the authors call for more work like this, and I second that call. The specific conclusions arrived at in this publication may or may not hold up under further study, but the process it demonstrates for getting them will be helpful in moving forward and getting more complete and reliable answers.

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Looking East from Casamero Pueblo

Looking East from Casamero Pueblo

Unmanned aerial vehicles (UAVs), popularly known as “drones,” have become increasingly common in recent years as the technology behind them has developed. Some uses are controversial, such as military applications and uses that might violate privacy expectations or be dangerous to other aircraft, but other uses are more benign and can potentially open up new frontiers.

In archaeology, UAVs are increasingly being used for aerial photography and remote sensing in many places around the world. These are types of research that have been established for decades, but that until recently were prohibitively expensive for most archaeologists since they required both expensive camera equipment and the use of airplanes or helicopters. With the development of both lighter, less expensive cameras and UAVs that are robust enough to carry them, this type of research is now much more practical.

A recent paper by a team of researchers including Jesse Casana of the University of Arkansas and John Kantner of the University of North Florida reported on research using a UAV to take infrared thermal imagery, or aerial thermography, as well as color photography, of sites in the Blue J community south of Chaco Canyon, New Mexico. (Casana has the paper posted on his Academia.edu page.) Kantner has been studying Blue J and the surrounding area for several years and has come up with some interesting results.

Blue J is in an area at the southern edge of the San Juan Basin that is thick with Chacoan outlier communities, most of which date to fairly early in the Chacoan era and many of which were apparently abandoned while the Chaco system was flourishing. Casamero Pueblo is one site very close to Blue J where a great house has been excavated and is open to public visitation. These communities typically have one or more great houses and great kivas, and in fact it is unusually common for communities here to have multiple great houses compared to other Chacoan outlier communities. At Blue J, however, Kantner has so far not identified any great houses or great kivas. As he says on his website:

Turquoise, marine shell, jet, azurite, malachite, and other exotic materials attest to the success of Blue J’s inhabitants. Oddly, however, what was originally thought to be a great house turned out to be a normal residential structure, making Blue J the only community for miles around without Chacoan architectural influence.

Now, part of what’s going on here may have to do more with how archaeologists define “great house” than with anything about Blue J specifically. The function of the monumental buildings that have been given this label remains a point of active contention among scholars, with some arguing that they were primarily residential, perhaps housing community elites or religious leaders, and others arguing that they were non-residential public architecture, perhaps with ritual significance as sites of pilgrimage and/or communal feasting. Kantner belongs to the latter camp, so finding “normal” residential features at a suspected great house removes it from consideration as such, whereas another archaeologist might interpret such findings differently. (It’s worth noting that many if not most excavated “great houses” have showed at least some evidence for residential use, and in some cases they have not been noticeably different from other residential structures in a community except in size and location.)

The focus of the recent study was on demonstrating the potential for using UAVs to do fast, inexpensive survey of large sites and to identify buried features. Blue J is well suited for this on both counts. It is located at the foot of a steep cliff, which has resulted in many sites in the community being covered with substantial deposits of sediment carried by water and wind, making them difficult to identify on the surface. It is also fairly large for a Chacoan outlier community, with over 50 residential sites identified through previous surveys, which makes a fast method of survey over a large area an attractive proposition.

The study consisted of doing several flights with a UAV over the site, at different times of day and night, primarily with the infrared thermal camera to capture differences in temperature that are expected to be present between archaeological features and the dry desert soil. The original intent was to do some of the flights in the hottest part of the afternoon, but high winds ended up making this impossible. The results were nevertheless impressive: one site that had been previously identified through survey and limited excavation showed up clearly in the imagery, with buried walls visible in some of the images. Several other sites that had been identified but not excavated showed up as well, with buried walls again visible. A large circle showing a possible great kiva is particularly interesting given that no great kiva has yet been identified from surface survey.

Obviously further work is necessary to confirm some of the results from the imaging, but this is a very successful demonstration of the potential for this technology to improve survey and site identification so that further research can be focused on the most promising locations for sites. Other sensing techniques such as ground-penetrating radar have also been tried in the Southwest, but they are much slower and can be thrown off by some characteristics of the desert environment. Aerial thermography using UAVs offers another option that seems to have a lot of potential and it will be interesting to see how it is used as the technology continues to advance.
Casana, J., Kantner, J., Wiewel, A., & Cothren, J. (2014). Archaeological aerial thermography: a case study at the Chaco-era Blue J community, New Mexico Journal of Archaeological Science, 45, 207-219 DOI: 10.1016/j.jas.2014.02.015

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Looking East from Peñasco Blanco

Looking East from Peñasco Blanco

Today is the winter solstice, which means it’s also the sixth anniversary of this  blog. On these anniversaries I like to write about archaeoastronomy, which is a very interesting topic and an important one for understanding Chaco and Southwestern prehistory in general. Last year I wrote about some research indicating that in the Rio Grande valley, an area generally thought to be outside the Chaco system but that was certainly occupied at the same time as Chaco, there was a long and very consistent tradition of orienting pit structures to the east-southeast, which is the direction of winter solstice sunrise. The winter solstice is very important in the cosmology and rituals of the modern Pueblos, so it makes a lot of sense that at least some Pueblo groups would orient their dwellings based on it.

As I noted at the time, this orientation is very different from that in the San Juan region to the west, including Chaco and Mesa Verde. In this area there is an equally long tradition of orienting pit structures to either due south or south-southeast. I’ve long wondered why this might be, and an article I read recently discusses the issue and proposes some interesting potential answers.

The article is by Kim Malville and Andrew Munro and was published in the journal Archaeoastronomy in 2010 as part of a special issue on archaeoastronomy in the Southwest. Malville is an astronomer who has done a lot of research on archaeoastronomy in the Southwest and identified many potential astronomical alignments, but this article is actually largely about debunking many of the alleged alignments claimed by others, particularly Anna Sofaer and her Solstice Project. Sofaer, an artist who turned her attention to archaeoastronomy after discovering the “Sun Dagger” effect involving a spiral petroglyph on Fajada Butte that on the summer solstice appears (or appeared) to be bisected by a “dagger” of light coming through a slit between large boulders in front of it. Sofaer went on to organize surveys of the major great house sites in Chaco Canyon to identify any celestial alignments in the orientation of their walls, and her team found that virtually all of them did show alignments to the positions of the sun or moon on solstices, equinoxes, or lunar standstills.

Light Snowfall on Fajada Butte

Light Snowfall on Fajada Butte

Sofaer and her collaborators went on to publish these findings widely, and to make a well-known documentary that has often been shown on television and inspired a lot of interest in Chaco. As Malville and Munro show in this paper, however, the evidence for these alignments is very thin. There is little to no justification in Pueblo ethnography for the idea of celestial building alignments, and the alignments themselves are identified with a substantial margin for error that makes spurious positive identifications likely, especially when so many potential alignments are tested for. Particularly concerning is how many of the alignments are to the minor lunar standstill, which is not a very impressive or noticeable event. (The major lunar standstill is a different story, and there is strong evidence at Chimney Rock in Colorado that the Chacoans were familiar with it and considered it important.) Malville and Munro also argue that the fact that most of the alignments are based on the rear walls of sites is also questionable, since there is no evidence that rear wall alignments were or are important culturally to Puebloans.

Instead, they argue that the alignments of rear walls are epiphenomenal, and that they mostly result from the more solidly established concern with the orientation of the front of a site. The bulk of the article is devoting to tracing these frontal orientations across time and space, with a primary focus on Chaco itself and on the earlier Pueblo I villages in the area of Dolores, Colorado that are often seen as being partly ancestral to the Chaco system.

As I noted above, there are two main orientations that persist through time in the San Juan region. One is to due south, and the other is to the south-southeast (SSE). With pit structures these axes are typically defined by a straight line of sipapu (if present), hearth, deflector, and vent shaft. There is often also a measure of bilateral symmetry between features on either side of this line, such as support posts. When there are surface rooms behind a pit structure, they often (but not always) conform to the same alignment, and when the back of a row of surface rooms is straight, it is typically perpendicular to the main orientation. Malville and Munro argue that these perpendicular back walls on many Chacoan great houses, which Sofaer has identified as having alignments to various astronomical phenomena, are really subsidiary effects of the main emphasis on frontal orientation.

The authors start their survey of orientations with the Basketmaker III pithouse village of Shabik’eschee at Chaco. Of 15 pithouses for which they could find adequate information on orientation, 11 faced SSE with an average azimuth of 153.7 degrees and 4 faced south with an average azimuth of 185 degrees. Strikingly, none of the pithouses showed any other orientation.

The north-south orientation isn’t difficult to understand, and Malville and Munro attribute it to use of the night sky for navigation (which would have been easy enough at this time even though there wasn’t actually a north star), and they also mention the widespread presence of Pueblo traditions mentioning origins in the north. While the exact reasons for adoption of this orientation may not be clear, its consistency isn’t unexpected since it’s pretty obvious and easy to replicate.

The SSE orientation, on the other hand, is a different matter. Note that at Shabik’eschee this was much more common than the southern orientation, from which it is offset by about 20 to 30 degrees in individual cases. There is more variation in this orientation than with the southern one (standard deviation of 7.7 degrees versus 2.4), but it’s sufficiently consistent and common that it seems like there must be some specific reason for it. Unlike the southern orientation, however, it’s not at all clear what that might be. Malville and Munro, sticking to their interpretation of orientations as references to places of origin, suggest that in the case of Shabik’eschee it might reflect the fact that some people might have migrated to Chaco from an area that was more to the north-northwest than due north, which seems implausible to me but then I don’t have a better explanation myself.

McPhee Reservoir, Dolores, Colorado

McPhee Reservoir, Dolores, Colorado

In any case, this pattern continues through time. The next set of orientations Malville and Munro look at are those of the pit structures at the Pueblo I Dolores villages. What they find is that SSE orientations are dominant here too, even more so than at Shabik’eschee. In fact, all of the pit structures they looked at had SSE orientations except those at Grass Mesa Village, which mostly faced faced south (although even here there were a few SSE orientations). This is in keeping with other evidence for differences in architecture among different villages at Dolores; Grass Mesa is known for having long, straight room blocks, as opposed to the smaller and often crescent-shaped roomblocks at McPhee Village, which with it is most often compared.

The Duckfoot site, to the west of the Dolores villages but contemporaneous with them, also had a SSE orientation. Further west, however, southern orientations become more common, including at the important village sites of Yellow Jacket and Alkali Ridge, plus some of the earlier Basketmaker II sites on Cedar Mesa in Utah.

There was one more orientation used during the Pueblo I period in the Northern San Juan region, however. At Sacred Ridge, in Ridges Basin near modern Durango, Colorado, the average azimuth of the pit structures is 120 degrees, the same east-southeast orientation corresponding to winter solstice sunrise so common in the Rio Grande. Malville and Munro remark on the similarity to the Rio Grande pattern and consider it “puzzling,” positing some potential ways that it could have come about. They argue, however, that wherever this pattern came from it didn’t last in the north, and they point to the extremely violent end to the occupation of Sacred Ridge as the end of this orientation tradition in the San Juan region (although this may not be strictly true, as discussed below).

From here Malville and Munro turn back to Chaco. Specifically, they look at the great houses at Chaco during its heyday from about AD 850 to 1150. Rather than pit structures, they focus on roomblocks, and they interpret the orientation of a roomblock to be the perpendicular to its long axis (in the case of rectangular roomblocks) or the perpendicular to the ends of the crescent of roomblocks with that shape. They find that most of the great houses have a SSE orientation, in keeping with the general trend throughout the region, as do the three northern outlier great houses of Chimney Rock, Salmon, and Aztec. Since this orientation is very close to the perpendicular of the minor lunar standstill moonrise alignment that Sofaer has proposed for many of these buildings, Malville and Munro argue that this widespread orientation explains the pattern much better than the lunar alignment. Pueblo Alto and Tsin Kletzin have north-south orientations, which is unsurprising since they lie on a north-south line with each other.

A few of the great houses have a more complicated situation. Peñasco Blanco appears to face east-southeast at an azimuth of approximately 115 degrees. This is intriguingly close to the Rio Grande/Sacred Ridge winter solstice orientation, which Malville and Munro do note. Although the unexcavated nature of the site makes it hard to tell for sure, it is possible that this is in fact an example of this orientation surviving much later in the San Juan region than the destruction of Sacred Ridge, although what, if any, connection there might be between the two sites is unclear.

Pueblo Bonito from Above

Pueblo Bonito from Above

And then there’s Pueblo Bonito. While the very precise north-south and east-west cardinal alignments of some of the key walls at this site are well known, it has also long been noted that there is evidence for different alignments and change over time here. Malville and Munro interpret the early crescent shape of the building as having a SSE orientation, and like many others they relate it to the similar size, shape, and orientation of McPhee Pueblo at McPhee Village. They then describe multiple stages of drift away from this orientation toward the cardinal orientation. There is surely something to this interpretation, but a careful look at the stages of construction of the site shows that the picture is probably more complicated. The very first construction at Bonito appears to have been straight and oriented to the south, and to have been incorporated later into the SSE-facing crescent. Subsequent building stages show evidence of both orientations having been present throughout the history of the building.

The complicated situation at Pueblo Bonito provides a convenient segue to the key issue here: what was driving this long-term but consistent variation? Why were two different orientations for buildings present in close proximity for hundreds of years, even as populations moved long distances and adjusted their cultures in profound ways? Malville and Munro suggest that these orientations may reflect longstanding cultural and ethnic diversity in the prehistoric Southwest. Given how long-lived and consistent these patterns are, they propose that they were related to deep-seated cultural identities. This is an intriguing idea that may allow tracking of specific cultural groups across the Southwest over centuries. It also provides another piece of evidence that Chaco Canyon was a multicultural community, and implies that even Pueblo Bonito itself contained groups with diverse backgrounds.

The picture is probably even more complicated than Malville and Munro suggest. They tend to implicitly assume that the orientations of pit structures are the same as those of the room blocks with which they are associated, but at least at Chaco this is not necessary true, particularly for small-house sites, which they also don’t address at all in this study. There are many examples of small houses where the room blocks are oriented to the east but the pit structures are oriented to the south (and possibly also SSE, although I haven’t checked this). This eastern orientation may reflect connections to the south, which have gotten a lot less attention in the literature than connections to the north although they appear to have been pretty important in the origins of Chaco.

In any case, I think this is fascinating stuff. It may not be archaeoastronomy per se, but it seems like a fitting way to mark the solstice.
Malville JM, & Munro AM (2010). Cultural Identity, Continuity, and Astronomy in Chaco Canyon Archaeoastronomy, 23, 62-81

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Rio Grande from Coronado State Monument, Bernalillo, New Mexico

Rio Grande from Kuaua Pueblo, Coronado State Monument, Bernalillo, New Mexico

Today is the winter solstice, which also makes it the fifth anniversary of this blog. I tend to like to post about archaeoastronomy on these occasions, and as I mentioned in the previous post I’m currently in Albuquerque and have been reading up on the archaeology of the Rio Grande Valley. Luckily, a recent article I read has a very interesting archaeoastronomical proposal specific to this region, which makes everything come together nicely. Getting to that point requires some explanation of the context first, however.

Today the northern Rio Grande Valley is one of the main centers of Pueblo population, and this was also true at the time the Spanish arrived in the sixteenth century. It’s been clear to archaeologists since the late nineteenth century that the modern eastern or Rio Grande Pueblos belong to the same overall cultural tradition as both the modern western Pueblos (Laguna, Acoma, Zuni, and Hopi) and the prehistoric Pueblo sites found all over the northern Southwest. Within this overall cultural tradition, however, there are noticeable differences in certain aspects of culture between the Rio Grande Pueblos and those further west, as well as between both groups and the prehistoric sites. The long and complicated history of interaction between the Rio Grande Pueblos and the Spanish has both led to cultural changes in this region and made the modern Pueblo residents very reluctant to reveal information about their cultures to anthropologists. Both of these phenomena make understanding the background of Pueblo diversity exceptionally difficult.

As a result, archaeological research in the northern Rio Grande area has proceeded along a somewhat different course from research further west. While extensive early research at well-preserved abandoned sites at places like Chaco Canyon and Mesa Verde led to the formulation of a robust and well-supported relative chronological scheme by the late 1920s that was soon anchored by the absolute dates provided by tree-ring dating, fitting the Rio Grande sites into this sequence proved to be a challenge. Alfred Vincent Kidder’s extensive excavations at Pecos provided clear evidence of continuity between prehistoric and historic Pueblo culture, which allowed the historic Pueblos to be easily placed at the end of the sequence, aligning earlier developments in the east and west proved to be a challenge. Pecos itself was founded quite late in prehistory, and very few other prehistoric sites had been excavated in the Rio Grande area. The so-called “Pecos System” of chronology and culture history was actually based primarily on western sites, and over time it became clear that it didn’t fit the emerging picture of Rio Grande prehistory pretty well. That picture, based primarily on survey and excavation work done by the Laboratory of Anthropology at the Museum of New Mexico starting in the 1930s, by the 1950s resulted in a new framework for eastern Pueblo prehistory.

The main architect of the new system was Fred Wendorf, an archaeologist at the Museum of New Mexico who had done a lot of the work of documenting sites in the region. He published a paper in American Anthropologist in 1954 describing his proposed system, which consisted of five periods:

  • Preceramic: Before AD 600
  • Developmental: AD 600 to 1200
  • Coalition: AD 1200 to 1325
  • Classic: AD 1325 to 1600
  • Historic: AD 1600 to present

Contrast this to the Pecos System, as presented by Joe Ben Wheat in a paper published in the same journal in the same year:

  • Basketmaker II: Before AD 400
  • Basketmaker III: AD 400 to 700
  • Pueblo I: AD 700 to 900
  • Pueblo II: AD 900 to 1100
  • Pueblo III: AD 1100 to 1300
  • Pueblo IV: AD 1300 to 1600

The most obvious difference between the two systems is that the Pecos System contains more periods. A more subtle difference is that in the Pecos System all of the periods are associated with agriculture, which appeared quite early in the Four Corners area. Exactly how early was not quite clear in 1954; Wheat says it was “about the time of Christ.” In the Rio Grande, on the other hand, the Developmental was the earliest agricultural period in Wendorf’s scheme as well as the first ceramic one, preceded by a Preceramic period that was totally undated at the time but that Wendorf suggested may have lasted quite late, even after the beginning of the Developmental.

This pattern of delayed appearance of typical “Anasazi” cultural phenomena in the Rio Grande persisted throughout Wendorf’s scheme. He defined the beginning of the Coalition period by the switch from mineral to organic pigment in pottery decoration, a trend which had been gradually diffusing east from Arizona over the past few hundred years. Similarly, the beginning of the Classic was defined by the appearance of glaze-decorated ceramics, which had appeared a few decades earlier in the Zuni area. The Historic period began with the onset of Spanish colonization. In general Wendorf’s period definitions depended heavily on trends in pottery decoration, in contrast to the Pecos periods which were defined by a broad suite of material culture changes, with architecture especially important. One reason for this was that architecture and other cultural traits were bewilderingly diverse within each of these periods, especially the Developmental, and this diversity was apparent even with the very small number of excavated sites at that time.

Palace of the Governors, Santa Fe, New Mexico

Palace of the Governors, Santa Fe, New Mexico

Wendorf’s scheme was in conflict on various points with a different scheme for Pueblo culture history as a whole developed by Erik Reed of the National Park Service. After Wendorf’s paper was published, discussions between the two led to an updated version of it published under both their names the next year in El Palacio. This paper has been extremely influential and the framework it established has been used by most archaeologists in the Rio Grande area since. The basic outlines of the framework are the same as those in Wendorf’s 1954 paper, with the changes involving the correction of the numerous typos in that paper, the addition of data from more recent excavations, and a somewhat different discussion of attempts to correlate archaeological phenomena with the complex distribution of modern linguistic groups. The latter was a particular interest of Reed, whose theories on it had been criticized by Wendorf in the earlier paper. I find it interesting as well, but I won’t get into it here.

Instead my focus here is on Wendorf and Reed’s Developmental period. Wendorf originally defined this period based on extremely limited information as a time of low population, diverse architectural styles and settlement patterns, and evidence of cultural influence from the San Juan Anasazi to the west. Population was extremely limited until about AD 900, when many more sites appear to have been inhabited and sites began to appear in the northern part of the region for the first time. This is the time of the rise of Chaco, and local Rio Grande ceramics show clear similarities to Chacoan types. Some archaeologists, including Reed, had argued that this rise in population came from an actual immigration of people from the Chaco area, but Wendorf doubted this, pointing out that other cultural traits showed considerable differences from Chacoan patterns. He suggested that while there could well have been some immigration from the west at this time, it was more likely from somewhere like the Mt. Taylor area that was part of the general Chacoan sphere of influence but closer to the Rio Grande, and that the number of people was likely small.

Architecture during the Developmental period was varied, with site sizes ranging from ten to 100 rooms and one to four kivas. The kivas were round and lacked most of the typical Chaco/San Juan features such as benches, pilasters, and wall recesses. They also usually faced east, in strong contrast to Chaco kivas, which usually faced south or southeast, even when they were associated with east-facing surface roomblocks (a common pattern for small houses at Chaco).

While the Wendorf and Reed system has remained in general use among Rio Grande archaeologists, the Developmental period in particular has seen much more data emerge from subsequent research, much of it associated with cultural resource management salvage projects. Cherie Scheick argued in a 2007 article that the period was much more diverse and complex than Wendorf and Reed had portrayed it as, illustrated by two nearby and contemporaneous sites in what is now Santa Fe that nevertheless had quite different ceramic assemblages which would place on in the Developmental period and the other in the Coalition period based on the Wendorf and Reed system. (This sort of thing is a major flaw with chronologies based mainly on ceramic styles, since time is by no means the only factor affecting differences in pottery.) Basically there seems to have been a long transitional period between the Developmental and Coalition in which communities with a variety of ceramic styles existed in close proximity. In particular, the introduction of carbon pigments seems to have been more variable than Wendorf and Reed realized, and they coexisted with mineral pigments for a substantial period. Scheick also points out that, contrary to what some earlier researchers had thought, there are no particular patterns over time in the architecture, such as larger villages developing later in the Developmental period.

Lurking in the background of all this research is the question of the abandonment of the Mesa Verde region and whether any of the apparent increases in population in the Rio Grande correspond to an influx of people from that area. Wendorf and Reed placed this migration in the middle of their Coalition period, with the appearance of a ceramic type, Galisteo Black-on-white, that is very similar to late Mesa Verde Black-on-white, and various other changes in material culture in the region that accompanied a population increase. However, recent research in the Mesa Verde region itself has suggested that the depopulation was a longer-term process beginning much earlier than previously thought, so some of the changes in the early Coalition period, could also be due to immigration. The basic problem is that while there are plenty of individual examples of similarity between San Juan/Mesa Verde culture and Rio Grande culture over a long period of time, there are no sites showing a complete package of San Juan cultural traits. There seems to be an emerging consensus that this is because the migration was primarily not of entire communities moving as units but of smaller units (families or lineages) that joined existing communities in the target region, perhaps ones that they had had earlier contact with through trade or other activities.

Round Kiva at Kuaua Pueblo, Coronado State Monument

Round Kiva at Kuaua Pueblo, Coronado State Monument, Bernalillo, New Mexico

An additional piece of evidence for this idea comes from the paper I mentioned at the beginning of this post, published by Steven Lakatos in 2007. Lakatos did an analysis of features in Rio Grande pit structures (kivas) during the Developmental period. He looked at size, orientation, and presence or absence of a hearth, an ash pit, a deflector, and a ventilator in a total of 131 excavated pit structures in the Rio Grande Valley dating to AD 600 to 1200. He looked at specific types of each of these features and came up with a wide variety of statistical comparisons. The sample sizes for most of the subsamples he looked at are so small, however, that I doubt many of these comparisons are meaningful. His overall conclusions, however, are probably reliable.

Lakatos found that there is a consistent pattern of features in pit structures throughout the Developmental period: hearth, ash pit, deflector, and ventilator, sometimes accompanied by sipapu and/or ash grinding stone, in a row aligned to the east-southeast (average azimuth from true north of 118 degrees for the Early Developmental period and 123 degrees for the late developmental). This is in strong contrast to the San Juan (Chaco/Mesa Verde) kiva pattern, where ash pits are rare, other features like benches and pilasters are common, and orientation is usually to the south or south-southeast. Lakatos notes that this Rio Grande kiva pattern continues into the Coalition period and later, as kivas become more formalized community-scale integrative structures, and while all the features in the complex potentially had originally mundane uses, the formalization of the pattern and its persistence over time suggest that at some point it acquired ritual significance. He notes the ritual importance of ash to modern Rio Grande Pueblos as a way of explaining the ash pit and ash-grinding stone as ritual features. The persistence of the pattern into the Coalition period and beyond suggests to Lakatos that immigrants to the Rio Grande from Mesa Verde and elsewhere not only joined existing communities, but largely assimilated to existing religious and cultural practices in an area that had developed a distinctive identity already. Thus, the reason it is so hard to pinpoint continuity between San Juan and Rio Grande archaeological sites is that the San Juan immigrants changed their culture to conform to Rio Grande practices.

I’m not sure I buy that there was quite as much continuity in the Rio Grande as Lakatos and other Rio Grande archaeologists tend to think. Looking at it from the outside, the ceramic evidence certainly seems to imply at least some continuity with Mesa Verde culture, and a close examination of what little ethnographic information is available on the Rio Grande Pueblos may reveal other traits of western or northern origin. Still, Lakatos’s evidence for continuity in kiva form looks convincing to me, and the patterns he identifies are certainly quite different from those of Chaco and Mesa Verde. The fact that his interpretation meshes well with other research suggesting migration by small groups into established communities is also encouraging.

So what does all this have to do with the winter solstice? Well, Lakatos also calculated the azimuth of winter solstice sunrise for the Albuquerque area in AD 1000, and it was 119 degrees east of north. This is strikingly similar to the average azimuths of the kiva alignments he analyzed, which have small standard deviations indicating strong clustering around the average values. The variation that does exist could easily correspond to local horizon variation in this rugged, mountainous region. Lakatos expresses surprise at this finding, but it makes perfect sense to me. The winter solstice is an enormously important event for the modern Pueblos, as Lakatos discusses, and pointing their kivas toward it would be a natural response to that importance. And with that in mind, I wish all my readers a happy solstice.

Lakatos, SA (2007). Cultural Continuity and the Development of Integrative Architecture in the Northern Rio Grande Valley of New Mexico, A.D. 600-1200 Kiva, 73 (1), 31-66

Wendorf, F (1954). A Reconstruction of Northern Rio Grande Prehistory American Anthropologist, 56 (2), 200-227 DOI: 10.1525/aa.1954.56.2.02a00050

Wendorf, F, & Reed, EK (1955). An Alternative Reconstruction of Northern Rio Grande Prehistory El Palacio, 62 (5-6), 131-173

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Mercer Museum, Doylestown, Pennsylvania

Mercer Museum, Doylestown, Pennsylvania

I was in Philadelphia for Thanksgiving, and the next day I went with my family to the quaint nearby town of Doylestown, where we visited two local museums: the Michener Museum (named after, yes, that Michener, who grew up in Doylestown and spent most of his life in the area) and the Mercer Museum. The Michener is basically a local art museum, and we went there to see an exhibit about Grace Kelly, who is a big deal in the Philadelphia area. Not really my kind of thing, but it was fine.

The Mercer, on the other hand, is a really unusual sort of museum. It was established by Henry Mercer, a Doylestown native who had a variety of interests and a good deal of money with which to pursue them. He studied law but never practiced it, instead going into archaeology in the 1890s. I haven’t found much information about his specific contributions to American archaeology, which was in its infancy at that time, except that he apparently supported the authenticity of the obviously forged Lenape Stone that allegedly contains an image of a mammoth and is now part of the Mercer Museum collections (though not on display).

In the late 1890s, however, Mercer came to the realization that the advancement of industrialization meant that most aspects of traditional life in the US were likely to disappear forever, and he began to collect what were then considered mundane objects for the museum of the Bucks County Historical Society. He collected huge numbers of things from all aspects of pre-industrial life, over time branching out to the US as a whole and eventually other parts of the world as well. His collection got so big that he built a new building to house it, using an innovative design and construction approach using poured concrete. He organized the collection thematically by the sorts of societal needs that objects served, and put together display cases by category.

The museum is still much as he designed it, although there have been various changes over the years. It’s a fascinating place, idiosyncratic and full of extremely detailed information. What I found especially interesting, however, was the way the museum’s own self-descriptions explicitly tied Mercer’s collecting of what most people considered “junk” to his earlier interest in archaeology. That is, one way to see what Mercer was doing was taking an archaeological approach to studying and preserving the material culture of the present and recent past, to ensure it would be understood in the future. This approach was quite ahead of its time for both history and archaeology, and the museum that resulted is fascinating and well worth a visit.

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