Chaco Is Closed

“Area Closed” Sign at Fajada Butte View

This is just a quick post to share some information likely to be of interest to my readers. There has been a lot of confusion about exactly how the National Park Service is responding to the government shutdown, which park units are accessible and not, and so forth. I’ve been pretty confused myself, and unfortunately this led me to give incorrect advice to a reader who asked if Chaco Canyon is accessible during the shutdown. I said my understanding, based on media reports, was that the parks are open but no visitor services are being provided. Since Chaco is mostly a self-guided experience, I took that to mean that the park would be accessible but the visitor center would be closed and no tours would be provided.

Well, the reader took my advice and headed out to Chaco, only to find that the gate was closed and the park was definitely neither open nor accessible. He let me know, and was nice about it, but I felt bad about leading him astray so I figured I would pass that information on here. Chaco is closed for the shutdown. Anyone planning to visit in the next few weeks should keep that in mind and monitor the news for information on when the government and the park will reopen.

If you do end up having to redirect a trip to Chaco as a result of the shutdown, Salmon Ruins in Bloomfield, New Mexico is one of the largest and most accessible Chacoan outlier sites, and since it’s managed by San Juan County rather than the federal government it is unaffected by the shutdown. Another option a little further afield is Edge of the Cedars in Blanding, Utah, which is a Utah state park and similarly unaffected. Most other Chacoan outlier sites that are open to the public are managed by federal agencies and will likely be inaccessible.

Edge of the Cedars Great House, Utah

In previous shutdowns parks have been closed entirely, which is the simplest and, from a resource-protection standpoint, most reasonable approach. This time it seems the NPS is taking a different and more complicated approach for reasons that are unclear. To try to get a better understanding of what exactly the NPS is doing with parks in this shutdown, particularly as it relates to Chaco, I took a look at the official NPS contingency plan. Two sections seem to explain what’s going on there:

As a general rule, if a facility or area is locked or secured during non-business hours (buildings, gated parking lots, etc.) it should be locked or secured for the duration of the shutdown.

This seems to explain what’s going on on the ground at Chaco, as reported by my reader who went there. The park loop road is ordinarily gated at night, so it appears that they’ve closed the gate for the duration of the shutdown. There are a few things to see on the way in to the park before the gate, but the vast majority of the sites and trails are beyond it.

At the superintendent’s discretion, parks may close grounds/areas with sensitive natural, cultural, historic, or archaeological resources vulnerable to destruction, looting, or other damage that cannot be adequately protected by the excepted law enforcement staff that remain on duty to conduct essential activities.

It’s possible that this section is also relevant, though it’s less clear. Certainly it would be best for resource protection to close all the major sites and trails; it’s hard enough for the law enforcement rangers to monitor visitor activity when the park is operating under normal circumstances. The test for this would be whether the attractions on the way into the park, particularly the Gallo Cliff Dwelling and the trail to Wijiji, are closed, which is not clear to me from the information I have. The park website currently says it’s closed entirely but without explanation of what that entails, so it may well be the case that this section has been invoked.

Hopefully the shutdown will be resolved soon and things will go back to normal, but for now it’s best to steer clear of Chaco. If I hear of any changes or get more information I’ll do another post.

Central Roomblock at Salmon Ruin

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An Observatory at Salmon Pueblo?

Salmon Ruins Sign

One of the most interesting chapters in Astronomy and Ceremony in the Prehistoric Southwest: Revisited reports on archaeoastronomical research at Salmon Pueblo (also known as Salmon Ruins), a large Chacoan “outlier” great house near modern Bloomfield, New Mexico. The paper is by Brooks Marshall and Larry Baker of the San Juan County Museum Association, which manages the site, and it argues that one particular room at Salmon was likely used as an observation station for both solar and lunar events.

The room, known as Room 82, is in the southeast corner of the central room block on the north side of the plaza, just southeast of the elevated “tower kiva” in the center of the block. When it was excavated in the 1970s, the excavators found that it had several unusual features that suggested it was used for specialized non-domestic purposes, though it was not clear to them at the time what those might be. In addition to the commonly found hearths, milling bins, and T-shaped doorways, there was an unusual opening in the east wall which Marshall and Baker call a “window” (unfortunately they don’t explain why they use this term, which is generally not used in describing Chacoan architecture), an adobe platform in the northwest corner that had two shallow pits at its north end, and a dividing wall in between of uncertain original height. The platform and wall were destroyed in the course of excavation, while the window has deteriorated a bit over time but is still there.

The unusual nature of these features and their east-west alignment made Marshall and Baker suspect an astronomical role, so in 2008 they created a replica of the adobe platform out of plywood and positioned it where they calculated it would be hit by light through the window at equivalent times to the original, taking into consideration the higher floor level due to backfilling of the room. In 2009, a stabilization project removed the backfill and allowed them to place the replica in the original location of the platform to verify their results. Further testing in 2010 and 2011 involved simulating the original size and shape of the window opening. Throughout these tests they placed two rocks on the platform to simulate the two pits at the north end of the original, known as Features 71 and 72.

Central Roomblock at Salmon Ruin

Their results were striking. They found that the northernmost pit, Feature 72, was lit by sunlight coming through the window only on the summer solstice, and when the original window opening was simulated the light was quite narrowly focused on this feature. Feature 71, despite being only a few centimeters away, was never lit up by the sun at all. It was, however, lit by moonlight during the major lunar standstill, when the moon rises at its most extreme position relative to the sun for a few years. It’s long been known that the first major period of construction at Salmon in AD 1089 and 1090 corresponds to the lead-up to a major lunar standstill, and indeed Marshall and Baker’s calculations showed that it was in these years that moonlight would have first illuminated the features at the north end of the platform. By the standstill itself, which lasted from AD 1093 to 1095, moonlight would have hit about three quarters of the platform. Marshall and Baker propose that the south end, which is never nit by moonlight, may have served as an observation point where someone could sit and observe the moonlight move across the platform over time, possibly allowing the prediction of the standstill.

Obviously the wall in between the window and the platform adds a complication to all this, as it would have blocked at least some light from coming through. There’s no way to tell how high it initially was, so Marshall and Baker ran some calculations based on different heights to see how they effected the illumination patterns they documented. They found that at a certain height the wall would have prevented the beam of light coming through the window from moving beyond the platform onto the floor, which may have been intentional. At higher heights it would have blocked the beam entirely, but the base of the wall was fairly thin and probably couldn’t have supported a full-height wall.

Excavated Rooms at Salmon Ruin

This is exciting research for several reasons. It’s always interesting to see a careful study of architectural alignments to celestial phenomena that takes into consideration excavation history and possible confounding factors. It’s particularly interesting that this study seems to have shown strong evidence for alignments even taking those other factors into consideration. The solstice alignment seems like the best established to me, which is unsurprising since solstice alignments in general are the best documented phenomena in ancient Pueblo archaeoastronomy. What I find most intriguing, however, is the possible lunar alignment and its relation to the construction dates at Salmon, since despite a lot of talk about lunar alignments at Chacoan sites very few have been securely documented, and unlike solar alignments there is no support for them in modern Pueblo ethnography. If this lunar alignment really does hold up, it helps strengthen the argument that the Chacoans really did observe and care about these subtle lunar cycles.

The strongest evidence so far for Chacoan observance of lunar standstill cycles comes from Chimney Rock Pueblo, further north in Colorado. The evidence here is quite strong indeed, as the full moon rises between twin spires of rock as seen from the great house only during the major lunar standstill, and this accounts for the otherwise very puzzling location of the great house atop a high, steep mesa. There is also some evidence from the dates of construction at Chimney Rock that some building periods were related to specific lunar cycles. The lack of support from other Chacoan sites, however, has made the seemingly solid evidence fr,om Chimney Rock hard to integrate into the picture as a whole. If people at Salmon, which is fairly close to Chimney Rock and is connected to it by an easy travel corridor along the San Juan River, were also marking the lunar standstill cycle, the picture begins to fill out a bit.

That said, this research is still fairly preliminary and I wouldn’t go as far as to say that the lunar alignment proposed here has been definitely established. More research is certainly necessary to confirm and interpret the patterns documented here. It is certainly suggestive, however, and very interesting.

Backfilled Rooms at Salmon Ruin

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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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The Complications of Corn

Metate Incorporated into Wall Capping, Pueblo Bonito

I’ve written a bit about the recent research, spearheaded by Larry Benson of the USGS, into the sources of the corn found at Chaco.  These studies continue to refine the techniques used to identify source areas, but so far they have shown that corn was almost certainly being imported to Chaco both during and after the florescence of the Chaco system between AD 1030 and 1130.  As they begin to test more potential field areas, of course, the number of matches for the strontium isotope ratios in the corn at Chaco has increased.  While early studies indicated that much of it likely came from the Chuska Valley, it now looks much more likely that it instead came from the area along the Chaco River between there and the canyon.  This is an area with numerous outlying great houses, and it was probably the main route for the many commodities from the Chuska area that were brought to the canyon, and it’s also generally a better area for agriculture than the canyon itself, so this all makes sense.  There has also been some evidence that at least some corn was also coming from the Totah area to the north, again a more productive agricultural area with many Chacoan outliers.

Based on the proveniences of the corncobs from Pueblo Bonito that were tested early on, one tentative suggestion emerging from this research was that the main sources of imported corn changed over time.  The cobs that came from the lower Chaco River were from Rooms 3 and 92 in the northern part of Old Bonito, one of the earliest parts of the building to be built, while the one cob of possible Totah origin came instead from Room 170, in the southeast corner, one of the newest parts of the site.  Since there does seem on other grounds to have been a shift in the emphasis of the Chaco system from south to west to north over time, it would make sense that the early rooms contained early cobs from the west while a later room contained a later cob from the north.

Talus Unit with Snow

A paper published in 2008 by a group of big names in Chacoan studies sought to look at this directly by radiocarbon dating the cobs.  This is an interesting paper which goes beyond that narrow topic to also look at the characteristics of the corn found at the various great houses and other sites.  One of the co-authors is Mollie Toll, a specialist in archaeobotany who has done a lot of research on Chacoan corn.  As part of that research, she had long noted that the corn at Pueblo Bonito generally had bigger ears with more rows of kernels than most other corn known from the prehistoric Southwest.    It was bigger than earlier and later corn, for one thing, but it was also bigger than most other corn from the same period.  Corn from the Chacoan occupation of Salmon Ruin was also unusually large, as was corn from the Talus Unit behind Chetro Ketl, but corn from Pueblo Alto and Pueblo del Arroyo, other contemporary great houses at Chaco, was smaller and more in line with that from earlier and later sites.

Toll came up with three possible explanations for the difference.  Pueblo Bonito corn could be a different variety or “landrace” from the others, which is plausible but not directly testable with current technology.  It could also have been grown outside of the canyon where conditions were better for agriculture, while the corn from other great houses was grown in the canyon where conditions were poorer.  Finally, and problematically, the corn at Bonito might not have been Chacoan at all!  Since modern corn is generally bigger than ancient corn, Toll (when she was first looking at this in the 1980s) couldn’t exclude the possibility that the corn found at Pueblo Bonito had actually been put there by Navajos in the nineteenth century.  Much of it was from George Pepper‘s excavations in the 1890s, so it couldn’t be newer than that, but there was no way for Toll to tell how much older it was.

Room 3a/92/97, Pueblo Bonito

We still can’t tell different ancient landraces apart (although the recent sequencing of the maize genome may make this more feasible in the future), but the strontium isotope testing is giving us a sense of where the corn was grown, and accelerator mass spectrometry now makes directly dating the corn relatively easy.  Seven cobs from Pueblo Bonito that had been used in the strontium studies were dated for this paper.  One was the cob from Room 170 that possibly came from the Totah, one was from Room 92, and the rest were from Room 3.

The results were illuminating, but also challenging.  All the cobs clearly dated to ancient times, so the possibility that the size of Pueblo Bonito’s corncobs represents recent deposition is effectively quashed.  Three of the Room 3 cobs had closely clustered dates with intercepts around AD 1000, which offered some partial support for the idea that the corn in the early rooms was relatively early, but the other two were widely spaced, one at 870 and at 1170.  This is problematic for the idea that the date of corn in a room can be predicted from the date of that room’s construction, but it makes sense that the deposits in a room may date to well after its construction.  Since Room 3 dates very early, probably to the 900s, it’s likely that the deposits there resulted from much later trash dumping once it was no longer used for its original purpose.  Room 3 has a firepit, so it was probably originally a residential room, and it is likely one of those “big square rooms” that I have argued began to take the place of kivas in Chacoan room suites of the tenth century.  Room 92 is part of the maze of confusing rooms next to Room 3.  It had a well-preserved floor with corn and bean bushes on it (it’s not clear from Pepper’s description if this was the second or third floor), which suggests that it was used as a storeroom at the end of the period of occupation in this part of the building.  The cob from this room had the latest date of any in the study, with an intercept of AD 1220, which is consistent with the idea that this room was in use as a storeroom at the end of occupation.

Room 170, Pueblo Bonito

The biggest surprise, however, was the cob from Room 170, which dated to AD 1010.  This is particularly odd, since Room 170 was probably built around 1080 or even later.  Looking at the probability curve for this date, there is some chance that the actual date was around 1100, but the curve as a whole has a much more prominent peak around the intercept at 1010 than any of the other reported dates, which suggests that the probability is quite high that the intercept does in fact represent the true date or close to it.  The authors give various possibilities for why the cob might have been placed in this room long after it was grown, including the idea that it was put there as some sort of ritual offering of continuity with the occupation of earlier parts of the building.  I prefer another explanation they also suggest, which is that it was part of an earlier trash deposit that was redeposited in Room 170 for some reason.  There is very little information on what the deposits in this room were actually like, but many of the rooms in this part of the building were full of trash when excavated, and I think it’s most likely that this one was too.  The trash could have been put there for any number of reasons; if it was redeposited from somewhere else, it may have served as structural fill to support an upper story.  In any case, this puts a damper on the idea that the overall sources of corn changed over time.  Indeed, the sources seem to have been pretty constant through time for cobs left in different areas of the site, which suggests that the real story is much more complicated.

One nice thing about this paper is that the authors do a very good job of properly reporting their radiocarbon dates, particularly in giving point estimates as intercepts, which are meaningful, rather than midpoints, which are not.  Many papers make this mistake, including some of Benson’s reporting these and other dates on corn.  This paper also shows the probability curves for the dates, which give even more information.  This seems to be pretty common these days among Mesoamerican archaeologists, but it’s still quite rare in the Southwest, where radiocarbon dating has only recently become a major focus.  The availability of tree-ring dates, which are much more precise, has generally led Southwestern archaeologists to neglect radiocarbon, but it’s becoming increasingly obvious from studies like this one that the ability to date things other than trees is very useful in interpreting sites.

Obviously this paper just reports a handful of dates, and the authors take pains to point out the tentative nature of any conclusions they draw, but it’s an important contribution to the issue of where the Chaco system, whatever its nature, was getting its means of support.  As is often the case with new avenues of research, at this point papers like this pose more questions than they answer, but there are plenty of corncobs out there to date and analyze in other ways, just as there are plenty of potsherds to test for theobromine.  Once we get a bigger database of dates and strontium (and other) ratios, we’ll start to get a clearer picture of the behavior behind these remains.

Metate Fragment at Pueblo Alto

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Back to the Square Rooms

Peñasco Blanco

Returning to my theory that the large square rooms with hearths and other residential features found at some great houses in Chaco and elsewhere were in some sense replacements for earlier kivas, I think the best evidence for this at Chaco itself (as opposed to at outlying great houses like Salmon) comes not from Pueblo Bonito, which is just too complicated a palimpsest to make something like this easy to see, but from the other early great houses: Una Vida and Peñasco Blanco.  These at least seem to have simpler layouts than Bonito, though the extent to which this is just an effect of their being (mostly) unexcavated is unclear.  Nevertheless, at least some parts of these two great houses do seem to show basically the pattern that I’m proposing for the development of residential room suites at great houses.

To recap the idea: The very earliest great houses, those built in the AD 800s, seem to show a pattern of suites similar to that seen at small houses or unit pueblos, with each suite consisting of one rectangular room backed by two smaller rooms.  In front of each roomblock there are subterranean kivas, usually with slightly fewer than would be expected if each suite had its own kiva.  This suggests to me that the suites housed individual nuclear families, but that they were grouped into larger units, perhaps extended families, which shared kivas.  Whatever rituals these residential units would have conducted would probably have been in the kivas, but for the most part these were still residential structures, similar to the pithouses occupied in earlier centuries but with some of their functions transferred to the rectangular front rooms of the roomblocks.  The smaller rooms in the back would have been used for storage.  A typical great house would contain a few of these suites, with a kiva for every two or three.  It’s unclear what the relationships among different kiva-units within a great house would have been, but they could have either been separate extended families within the same real or fictitious “clan” or “lineage,” or they could have been separate lineages that were politically or ceremonially allied.  Importantly, all of these buildings are still residential at this point, although the residents may well host rituals or feasts open to the whole community either to solidify their political authority or because generosity is expected of them in exchange for community acceptance of their greater wealth or political/religious authority.  The main difference between great houses and small houses is just that great houses are bigger, with multiple stories in some instances and generally bigger rooms, as well as more extensive use of masonry rather than adobe or jacal construction.

Room 330, Pueblo Bonito

Then, at some point in the 900s, a change takes place in some (all?) great houses.  Use of the kivas is discontinued, and instead the activities that had been conducted in them are transferred to square surface rooms added onto the existing roomblocks.  This definitely seems to be what happens at Una Vida and Peñasco Blanco, although the extent to which there were earlier kivas is unclear given the lack of excavation.  In great houses newly begun during this time (it’s unclear how many of these there were in Chaco itself, but Kin Nahasbas may be an example), room suites were built without any kivas but with large, square rooms in front and smaller rectangular rooms varying in number behind them for storage.  This pattern continues well into the 1000s, at least at some great houses, and it’s associated with the very formal, symmetrical, rectilinear layout seen at sites such as Hungo Pavi, Chetro Ketl, and Pueblo Alto.  Some outlying great houses, such as Kin Bineola and (especially) Salmon, show this pattern as well.  Salmon seems to show that new great houses with (almost?) exclusively square rather than round living rooms were still being built as late as 1090, and if the early construction at Aztec is in the same pattern, which seems to be a matter of some dispute, it would still be going on well into the early 1100s.  This is probably also what we see at Pueblo Bonito too, with the possible addition of square rooms like 329 and 330 to the older suites at the west end of Old Bonito and the later addition of linear suites to the south of these rooms at the southwest corner of the site.

At some point in the late 1000s, however, a different type of room suite begins to arise at some Chaco great houses.  This is still a linear suite, sort of, but it consists of a round kiva built aboveground into a first-story square room, with one or two rows of two- or three-story rectangular rooms extending back from it.  These are the “blocked-in” kivas that are probably the most famous innovation of Chacoan architecture.  I see them as still residential spaces, in combination with the rooms behind them.  Their appearance at most outlying great houses indicates residential use of those sites, perhaps by local elites.  It’s not clear what the relationship is between these plaza-facing blocked-in kiva suites and the “elevated” kivas surrounded by rectangular rooms that start to appear at the centers of the rectilinear great houses with the square living rooms around this same time.  If those rooms are still residential, they’re pretty damn fancy residences.  They’re also quite unlike the other residential rooms at these sites, which are still square.  The “Tower Kiva” at Salmon is one example, as are the corresponding kiva at Hungo Pavi and the numerous examples at Chetro Ketl.  The central placement and unusual elaboration of these structures has led many to assume that they were ceremonial rather than residential in function, but I’m not so sure.  These sites do generally have great kivas, which pretty much everyone agrees were community-scale ceremonial/integrative structures, and they look quite different from elevated kivas (although it’s not clear to what extent the unique features of great kivas are due to structural requirements following from their size).

Kivas in the Southeast Part of Pueblo Bonito

In any case, the best examples of the plaza-facing blocked-in kiva suites are at Pueblo Bonito in the southeast and southwest wings.  These appear to have been built over earlier construction, so it’s not totally clear what was going on with these multiple, quite rapid changes in site layout during this period.  Again, though, they’re also obvious at Una Vida and Peñasco Blanco, where some (but not all!) of the earlier square living rooms are replaced by blocked-in kivas.  This also appears to have happened in the west wing of Chetro Ketl, but it’s unexcavated so it’s hard to say for sure.  There definitely are two blocked-in kivas there, though, and they appear to have rooms behind them like at Pueblo Bonito.

Then, at some point toward the very end of the eleventh century or very early in the twelfth, a totally new type of room suite begins to appear at Chaco great houses.  This is the famous “McElmo unit,” with a central blocked-in kiva surrounded on three or four sides by rectangular rooms, most of them significantly higher (three or four stories), creating a sort of “patio” over the kiva.  These rarely have ground-floor exterior walls, and they are remarkably uniform and modular in form.  The most famous of these structures are the freestanding ones, including New Alto, Casa Chiquita, and Kin Kletso (which comprises two adjacent units), but clearly analogous forms can be seen within certain great houses, including the north and south wings of Pueblo del Arroyo and the Kiva B complex at Pueblo Bonito.  Similar units that are just outside of existing great houses can be seen at Chetro Ketl and Peñasco Blanco.  The masonry of most of these is very different from that used at earlier great houses, being composed of blocky yellow sandstone rather than fine, hard, dark sandstone, and this has been used to argue that they represent influence from the north.  The masonry may indeed reflect northern influence (though in a different way from what the original proposers of this idea thought), but the form predates the shift in masonry and probably developed locally in Chaco.

Kiva E, Kin Kletso

There has been a lot of debate over the function of McElmo units.  Some see them as warehouses, while others see them as ritual (or possibly astronomical) special-use sites.  I’m increasingly thinking that all this speculation is based on an overemphasis on their differences from earlier great houses, and that they were probably residential and represent the final version of the Chacoan room suite.  More on this later.

McElmo units may represent the final development of Chacoan architecture in terms of form, but the great houses continued to be occupied for quite some time after the construction of these roomblocks in the early 1100s.  What we see at this point is an increased emphasis on the blocked-in kiva concept, with new kivas, often of “non-Chacoan” form, being built into earlier square or rectangular rooms.  Some call these “intra-mural” rather than “blocked-in” kivas, to emphasize that they were built into earlier rooms rather than having square rooms built around them, and I think this is a helpful distinction.  These really proliferate at Pueblo Bonito late in the occupation period, and this also happens at Aztec and Salmon during their “post-Chacoan” (also called “secondary” or “Mesa Verdean”) occupations.  At the same time, many great houses also see the construction of new subterranean kivas in the plazas, often with accompanying small blocks of square rooms.  These aren’t usually datable directly, but they appear to be very late.   Pueblo Bonito has particularly many of these, and there are a few in the southeast corner of Chetro Ketl too.  These appear to represent the construction of typical small-house or unit-pueblo style residential units within earlier great houses, and they may or may not represent an occupational discontinuity of some sort.

So basically, what we see is a sequence of underground kiva to above-ground square room to above-ground kiva.  There are plenty of variations and complications, but that’s the general sequence.  The later use of intra-mural kivas, especially at Pueblo Bonito, has tended to obscure the middle stage here, but it really seems to represent something meaningful at least as a chronological marker in Chacoan architecture.  Does it mean anything else culturally?  That part I’m still looking into, but it may.

Fajada Butte from Una Vida

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Was the Salmon Area Actually Uninhabited When the Chacoans Showed Up?

Shannon Bluffs, South of Farmington, New Mexico

One reason for the relative lack of information available on the prehistory of the Totah is that the presence of all those big rivers leads many sites to be buried under alluvium and/or destroyed by flooding and changes in the courses of the rivers.  As a result, many sites are not visible at all on the surface, and this is particularly the case for small sites, especially since the local architecture for much of the Pueblo period relied heavily on adobe and cobble masonry, which is much less durable than the sandstone masonry typical of Chaco and Mesa Verde.  Thus, aside from really big sites like Salmon and Aztec, many Totah sites are only discovered with very deep excavation or erosion.

Linda Wheelbarger’s chapter in the Salmon synthesis volume, reporting on the findings of the Totah Archaeological Project on the Bolack Ranch just south of Farmington, emphasizes this in pointing out how many of the sites on the ranch were not visible in any way from the surface and were only discovered inadvertently, such as when breaches in irrigation ditches lead to swift erosion, revealing sites well below the ground surface.  The most obvious sites are on the terraces above the river, and these are also some of the largest sites (including some probable Chacoan great houses), but it’s not clear if they are actually the largest or if there are larger ones buried somewhere in the floodplain.   Most of the known floodplain sites are small houses, but they are quite numerous, and Wheelbarger is able to define five “communities” along the southern bank of the San Juan between the confluence of the Animas River to the west and the Gallegos Wash to the east.  These tend to be at the confluences of various side drainages (including the Animas and the Gallegos) with the San Juan, which is a pattern noted elsewhere in the San Juan Basin as well, including to some degree at Chaco itself.

Plaza at Salmon Ruin

This is something to keep in mind when evaluating the conventional wisdom that the area around Salmon Ruin was largely uninhabited when construction of the building began around 1090.  The basis for this very common assertion is an extensive site survey done in the area around Salmon by the San Juan Valley Archaeological Project in the 1970s in conjunction with excavations at Salmon.  This survey revealed only four small sites within 1 kilometer of the great house that might have been contemporary with it, and only 12 such sites within 6 km.  In his chapter on the function of Salmon in the synthesis volume, Paul Reed explains the survey and its limitations:

The survey did not entail 100 percent coverage because of the complexity of land ownership and lack of permission to survey some parcels.  Nevertheless, much of the territory in the 1 km area around Salmon was surveyed.  As a caveat, it is likely that flood deposits from the San Juan River, along with alternating cycles of erosion, may have concealed or removed other sites located on the floodplain below Salmon.  We have no way of knowing how many such sites may have been present.  With the data that are available, however, it is clear that Salmon was not the center of a large community of surrounding small pueblos; rather, Salmon largely comprised the entire community.

Reed is clearly aware that it is likely that any sites that may have existed on the floodplain are no longer visible, but he nevertheless concludes that “it is clear that Salmon was not the center of a large community of surrounding small pueblos.”  Well, no, it isn’t clear, even “with the data that are available,” unless you make the totally unwarranted assumption that the available data do in fact reflect the reality despite their obvious shortcomings.  It’s worthwhile to note that the handful of sites that were identified were mostly on the terraces, rather than the floodplain, which means that they don’t have much relevance to the issue of how many sites there were in the region overall.  It’s certainly possible that Salmon was founded in a vacant area, as Reed concludes, but it’s important to note (as he does) that this would make Salmon quite unusual among Chacoan great houses, which usually were built among contemporaneous small sites both in Chaco Canyon itself and at outlying communities.

West Wing of Aztec West and Terrace to the North

A somewhat comparable situation exists at Aztec, although there is evidence of a fairly substantial residential district on the terrace above the West and East great houses.  Very little is known about the extent of settlement on the floodplain around the main “downtown” district, and some have argued that Aztec, too, was founded in an area without substantial prior settlement (with the terrace-top houses presumed to postdate the initial construction of the great houses), whereas others have argued that there probably was some sort of existing settlement there that is no longer visible because of the river-side location.  In either case it is clear that Aztec was a larger and presumably more important community within the region than Salmon.

There isn’t any way to settle this issue without extensive testing and excavation, which is unlikely to happen any time soon, but I just want to flag it to emphasize that a lot of the ideas that get entrenched in the archaeological literature are not necessarily well founded, and it’s important to understand the evidence behind them and how strong it is.

Terrace North of Salmon Ruin with Salmon Museum at Top

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Why Do We Know So Little about the Totah?

Totah Theater, Farmington, New Mexico

In comments to my post on Salmon Ruins, John Barton asks for more discussion of this area, which is surprisingly poorly understood given its obvious importance to Southwestern prehistory as a whole and the Chaco system in particular.  Wolky Toll has a chapter in the Salmon synthetic volume discussing the Totah region (named from the Navajo name for the Farmington area), and particularly the La Plata subregion, which is becoming somewhat better understood due to a major salvage archaeology project along New Mexico Highway 170, which parallels the La Plata River from the Colorado border south to its confluence with the San Juan just west of Farmington.  Toll has played a major role in this project, and his chapter has interesting things to say about the Totah in general and the La Plata valley in particular.  I don’t really buy all of his interpretations of Chaco; he’s one of the major proponents of a view of Chaco as a regional ceremonial center drawing pilgrims from throughout the San Juan Basin, including the Totah, but with a minimal population permanently resident in the canyon.  He’s particularly associated with the view that even the small-house residents at Chaco only lived there for part of the year, having other residences in other communities, especially along the Chuska Slope to the west.  I’m more inclined to see Chaco as some sort of hierarchical system with at least a relatively large permanent population, mostly in the small houses, though I’m not sure which version of this idea (and there are many out there) I find the most convincing.

Still, Toll knows a lot about the Totah.  He even introduced the term to archaeological use in an important chapter in a previous edited volume that he coauthored with Peter McKenna.  One of the important points he makes in the newer chapter is that while this region has historically been treated as part of either the Mesa Verde region to the north or the Chaco region to the south, it really has an independent identity and cultural trajectory that has been obscured by seeing it entirely in terms of migration or influence from north or south.  This is not to say that the Totah was isolated from developments to the north and south; far from it.  It’s really more accurate to see the whole San Juan basin as a single cultural region, with remarkable uniformity in many cultural expressions and changes over time.  The specific manifestations of those cultural processes were not necessarily identical, of course, but there’s more similarity than archaeologists are often inclined to say.

Mesa Verde Museum

Part of the problem here is just the way archaeology developed in the Southwest.  As Toll notes, the activities of the Wetherill family had a huge influence on which areas came to be considered most important to the interpretation of regional prehistory.  They were not the only influential figures, of course, but they definitely did a lot to put Mesa Verde and Chaco specifically on the radar of the archaeological profession as well as the general public.  In any case, the way things developed was that Mesa Verde and Chaco became well-studied, with major excavation projects in the late nineteenth and early twentieth centuries producing huge numbers of artifacts and a general understanding of the chronological sequence of pottery types and other artifacts.  Once tree-ring dating provided an absolute chronology for the whole region, the general outline became clear: Chaco flourished in the eleventh century then declined in the twelfth, while Mesa Verde hit its peak later, in the thirteenth century, shortly before the whole region was abandoned around 1300.

This was a bit of a shift from the more evolutionary approach to culture history encapsulated in the original Pecos Classification, developed at the first Pecos Conference in 1927 and described by Alfred Vincent Kidder in a short article in Science at that time.  This system saw both Chaco and Mesa Verde, with their big, impressive masonry “pueblos,” as belonging to the Pueblo III or “Great Pueblo” period.  The tree-ring dates, however, showed that Chaco’s peak actually occurred earlier, coincident with the widespread small sites that marked the Pueblo II period.

Aztec West Great House, Aztec Ruins National Monument

Turning back to the Totah, the main excavation project there in the early twentieth century was conducted by Earl Morris at Aztec Ruins.  This was the largest site complex in the area, and it clearly indicated some level of social and cultural importance.  What Morris found there, however, instead of a unique and clearly indigenous material culture, was a mix of what seemed to be Chaco and Mesa Verde material culture.  The early deposits showed clear similarities to Chaco, as did the architecture of the site, which Morris interpreted as evidence for a close cultural connection to Chaco.  After this period, however, Morris saw evidence for an extended hiatus with little evidence of any sort of occupation or use.  After that there was another, quite different suite of material culture that looked much more like Mesa Verde.  Morris interpreted this sequence as an initial Chaco-affiliated occupation followed by abandonment and reoccupation by immigrants from the Mesa Verde region to the north.  In an important chapter in the Salmon synthesis volume, Gary Brown, Peter McKenna, and Tom Windes argue persuasively that Morris was actually wrong about this, and that while the construction and early occupation of Aztec does indeed show substantial connections to Chaco, there was probably not any abandonment or hiatus, just a period of somewhat reduced construction activity at a time of widespread drought and environmental hardship in the mid-twelfth century.  This lull was followed by extensive occupation and construction in the thirteenth century, especially at the east ruin (which Morris didn’t excavate).  The occupants at this time did have pottery similar to that used at Mesa Verde, but that doesn’t mean they were immigrants from there, and it’s much more likely that they were primarily local people who had been living at Aztec all along.  Everyone in the region at this point was making the type of pottery now known as “Mesa Verde Black-on-white,” and there’s no particular reason to think that any groups in the Totah had links to Mesa Verde, which itself seems to have been remarkably isolated during this period, with few trade goods found at the many excavated sites in the region despite its large population.  A similar story seems to obtain for Salmon, with an early Chaco-affiliated occupation followed by a period of continued occupation but little major activity, then an increase in population and activity before the final depopulation of the entire region.

So why did Morris get this wrong?  One reason, which Toll emphasizes, is that the mere fact that Chaco and Mesa Verde have been much more extensively studied than the Totah means that ceramic types (and other types of material culture, but pottery is the most important for cultural classification) have become associated with one or another of these areas, so that when they are found elsewhere in the region they are taken to indicate influence or migration from Chaco or Mesa Verde rather than a regionwide stylistic trend uniting all of these areas.  The latter is more likely, however, especially for the Totah, which was a major population and cultural center throughout the Pueblo II and III periods.  In her chapter in the Salmon synthesis volume, Lori Stephens Reed describes the discovery that the ceramic types found at Salmon and Aztec that have traditionally been classified as “Cibola” (Chaco) or “Northern San Juan” (Mesa Verde) types based on temper and design were mostly made within the Totah, judging from the type of clay used for the paste and slip of the vessels.  Rather than define new types, she just adds the qualifier “Animas Variety” to the existing type designations to indicate this local origin.  This makes sense from an Ockham’s Razor perspective, but as Toll notes in his chapter it’s really the type names themselves that have led to the downplaying of the local factor in the prehistory of the Totah.

Mesa Verde Escarpment from 2009 Pecos Conference at McPhee Campground

The best example of this is the very widespread thirteenth-century pottery type known as “Mesa Verde Black-on-white,” which is found all over the place but has tended to be interpreted as indicating some sort of influence or migration from Mesa Verde.  This is highly improbable, however, since Mesa Verde was gaining rather than losing people for most of this period (until the very end), and the people there don’t seem to have been very actively engaged in regional trade.  This strongly suggests that Mesa Verde Black-on-white is probably of local origin wherever it is found, despite the name.  Toll even muses more than once about how interpretations of Southwestern prehistory might be different if it were called “Aztec Black-on-white” instead.  It’s quite clear that Aztec was a very important site during this period, perhaps not as important as Chaco had been earlier but certainly more important than any single site in the Mesa Verde area.  And yet, because Mesa Verde has been more intensively studied, until quite recently it has been accorded an enormously important role in regional dynamics during this period that closer examination is revealing to be mostly undeserved.  Chaco has received a similarly privileged position for its period of florescence for similar reasons, but it seems to have actually been roughly as influential as this assumption implied.  (Something of an archaeological Gettier case.)

But why didn’t the Totah get the early attention that would have gained it the pride of place in Southwestern archaeology occupied by Chaco and Mesa Verde?  Ironically, a big part of the answer seems to be tied precisely to the geographic factors that made it such an important area in the first place.  One of the main reasons Mesa Verde and Chaco attracted early attention from archaeologists and pothunters was that their isolated locations left them unbelievably well-preserved.  The sites were very obvious on the landscape, many had stood relatively well due to either their massive construction (at Chaco) or their sheltered locations (at Mesa Verde), and they were sufficiently hard to get to that subsequent inhabitants and explorers hadn’t done them much harm.

Animas River, Farmington, New Mexico

The Totah, however, is an enormously attractive and productive agricultural area.  This is presumably what attracted people to Salmon, Aztec, and other communities in prehistory, and it definitely attracted huge numbers of Anglo settlers in the late nineteenth century who proceeded to plow over, loot, and otherwise damage the numerous archaeological sites they found before archaeologists had even heard of them.  The really big sites, like Salmon and Aztec themselves, managed to remain in relatively good condition until they could be professionally excavated, but innumerable smaller sites have likely been completely destroyed.

The local environment has also led to decreased visibility for these sites directly, by covering them with alluvial silt that makes them difficult or impossible to see from the surface.  As a result, we have little sense of how many sites are out there today, let alone how many were there initially before the farmers and the pothunters got to them.  Again, this is in contrast to the harsh environments of Chaco especially, and Mesa Verde to a lesser extent, where there are no permanent rivers to bury sites so deeply.  Furthermore, modern development in the Totah has been extensive, and there’s very little information about what lies underneath the rapidly growing modern towns of Farmington, Aztec, and Bloomfield.  For all of these reasons, the Totah remains surprisingly understudied, despite its obvious importance for understanding Southwestern prehistory.  Luckily this is starting to change a bit, at least on the conceptual level, with publications like Toll’s and Reed’s that point out the distinctiveness of this area and its independent identity.  The Totah has stood in the shadow of Chaco and Mesa Verde for a very long time, but it now seems to be finally coming into the light.

Chaco Street in Aztec, New Mexico

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Was the Difference between Round and Square Living Rooms Temporal Rather Than Geographic?

Room 329, Pueblo Bonito

When I initially proposed that the square, plaza-facing rooms at Chacoan great houses that have features suggesting residential use represented an alternative to residence in kivas, I speculated that the difference between the two patterns might reflect some meaningful social difference within Chacoan society, perhaps different ethnic or geographic origins.  I’m still willing to entertain that idea as a hypothesis, but after looking a bit more closely at the development of the well-documented great houses I think it’s more likely that what we see  here is a difference over time, with different styles of residential architecture predominating in construction projects dating to different periods.  Basically, it looks like the earliest great houses generally have subterranean kivas associated with suites of rectangular rooms, which is the standard pattern at small houses as well.  There are typically fewer kivas than there are room suites, which suggests that kivas might have been shared by multiple households (extended families?) living in close proximity.  At some point, however, probably in the tenth century, a new style emerged in which the kiva was replaced by an above-ground but single-story square room backed by two or three two-story (or even three-story) rooms that were smaller and more rectangular.  These are the “linear suites” well-known to Chaco architecture scholars.  It’s unclear how prevalent they were, and it doesn’t seem that they were ever universal at all great houses, but a substantial amount of great-house construction in the late 900s seems to be of this type, with no new kiva construction and older kivas possibly falling into disuse.

At some sites this pattern persists well into the late 1000s, such as at Salmon, and in general it seems to be typical at many later great houses with very formal, rectilinear, symmetrical layouts.  At some point, however, it seems to have been supplemented and ultimately replaced by a new pattern of building round kivas into aboveground square rooms, which in some ways seems like a combination of the two styles.  In some cases these kivas were actually built into what appear to have been square living rooms that had been built earlier; this is what happened at Salmon in the post-Chacoan era, but it also seems to have happened in some cases at Pueblo Bonito, probably still within Chacoan times.  Other examples of these “blocked-in” kivas were clearly built as units, with the square enclosure and the circular chamber built together.  It’s not clear exactly when this change happened, but it was probably in the late 1000s or early 1100s, right at the peak of Chaco’s power and influence or shortly thereafter.  Later, and definitely after Chaco’s decline, a new pattern arose, with kivas and associated surface room blocks strongly resembling those at small houses being built into the plazas of Chacoan great houses.  This probably also involved additional building of new kivas into older Chacoan square or rectangular rooms.  It’s not clear how long this persisted, as these late units are very hard to date, but it may well have gone on into the 1200s.

Any of these changes through time may well have been associated with changes in regional influence or social dynamics, and I’ll be  looking into the possibilities for explaining them, but I think it’s pretty clear that there’s a strong temporal component to these differences in architecture.  One implication of this is that while the large numbers of visible kivas at Chacoan sites have led to an idea that Chacoan architecture is associated with lots of kivas, it may well be the case that the most “Chacoan” innovation in domestic architecture is precisely a lack of kivas, and that this is not obvious today because it didn’t take and after a period of kivaless construction people, including Chacoans, went right back to building (and living in) kivas.  I’ll be thinking about and looking into other potential implications for understanding the Chaco system and its place in the broader region.

Kivas in East Plaza, Pueblo Bonito

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Salmon Ruins and Chacoan Residence Patterns

Salmon Ruins Sign

One of the largest and most important of the “outliers” associated with the system centered on Chaco Canyon in the late eleventh century AD is Salmon Ruin on the San Juan River near Bloomfield, New Mexico.  Salmon is about 45 miles due north of Chaco, and its location in a fertile river valley makes it a much less surprising (though still impressive) site than Chaco, with its stark, desolate setting.  Salmon was partly excavated in the 1970s by Cynthia Irwin-Williams of Eastern New Mexico University, and the Center for Desert Archaeology has recently been working on an extended project to collect, reevaluate, and publish data from those excavations as well as new analyses taking into account more recent discoveries and interpretations relating to the Chaco system in general.  One result of this was the publication of a comprehensive three-volume site report in 2006, and another was the publication of a shorter, more synthetic volume in 2008.  I read the report a while ago and am currently about halfway through the newer book.  It’s definitely more accessible than the report, but it doesn’t really stand alone.  A lot of basic information about the site and the excavations seems to be assumed, presumably because it’s discussed in the site report.  The report doesn’t stand alone either, and in general there’s a surprising lack of overlap between the two publications.  You might think that the synthetic volume would be a more accessible book aimed at a general audience, since it’s published by a university press rather than by CDA and the Salmon Ruins Museum, but while the new book goes well beyond Salmon itself in discussing the archaeology of the “Middle San Juan” or “Totah” region in general it really seems to be aimed at specialists with substantial background who have either already read the site report or are willing and able to find and read it if they want to follow up on the numerous references to chapters in it.  Both books are very expensive, which is another factor standing in the way of a general audience for them.

This is all rather unfortunate, because there’s a lot of important and fascinating information in these two publications.  In the context of my recent discussion of kivas at Chaco and the debate over their function, one of the chapters in the synthetic volume is particularly relevant.  Here Paul Reed, the head of the CDA project at Salmon, makes a strong case for a largely residential function for Salmon during the Chacoan period.  This is interesting in itself due to the longstanding debate over the function of great houses like Salmon in general, with some arguing that they served as primarily non-residential ceremonial structures while others see them more as elite residences.  Reed doesn’t discount the importance of ritual functions at Salmon, nor does he try to argue that all great houses were primarily residential, but he shows from the evidence collected by the excavations in the 1970s that there is abundant evidence for residential use of many of the rooms at Salmon during its brief Chacoan occupation as well as during its longer subsequent occupation, which he sees as being by local people after the Chacoan residents left and went to Aztec.

Excavated Rooms at Salmon Ruin

One of the most important pieces of evidence Reed points to to support a residential function at Salmon is the very obvious presence of room suites throughout the site.  Salmon has a very formal, “planned” layout typical of later great houses, which makes sense since it seems to have been founded around 1090, toward the end of the Chacoan era (which lasted from about 1030 to 1130).  Indeed, it looks virtually identical in layout to Hungo Pavi, an unexcavated great house in Chaco Canyon about which little is known.  Salmon, like Hungo Pavi, is an “E-shaped” great house, with a central room block on the north side and wings extending to the south at the east and west ends.  The whole thing seems to have been constructed as a single unit within a few years around 1090, which makes it by far the largest single building episode known in the Chaco system and has interesting implications for understanding why it might have been built.  There has long been a dispute over whether the outliers in the Chaco “system” represent direct colonization by people from Chaco, local emulation of Chacoan forms by emerging elites, or something else.  Reed supports a colonization model, but he sees the Chacoans who came up to Salmon and built the great house as having also brought local residents in to live there with them, and perhaps to work on building the thing too.  The local area seems to have lacked a substantial pre-Chacoan population, so it’s not entirely clear where these locals would have actually come from, but it does make sense that colonists from Chaco would have selected a relatively uninhabited location for their new settlement.

Anyway, back to the room suites.  Most of the site seems to have originally been laid out as a series of suites, each of which involved a large square room facing the plaza connected to three smaller rooms behind it.  The large square rooms seem to have been single-story, but the smaller rooms mostly had two or three stories.  The large square rooms especially tended to have many residential features such as hearths, and the smaller rooms often had features such as milling bins that also suggest domestic use.  There were also a few rooms that had very large milling bins, larger than would have been necessary for individual households, which suggests that site residents might have been grinding corn on a large scale.  This, combined with Salmon’s location in a fertile valley, in turn suggests that the site may have been founded partly or even primarily as an agricultural colony that would have exported corn and/or cornmeal to Chaco and perhaps other areas with poorer agricultural potential.  There is evidence from studies of corn at Chaco that much of it was imported from the Totah, which meshes nicely with this idea.

Backfilled Rooms at Salmon Ruin

The key thing here, though, is that it’s the large square rooms that seem to have been the primary living rooms.  This is similar to the case at some early room suites at Chacoan great houses, such those in the western wing of Pueblo Bonito.  Later great houses at Chaco seem to have largely either lost the room suite pattern or modified it beyond recognition, but at Salmon it stands out clear as day.

There’s something missing here, though.  Salmon (in the Chacoan period) was composed almost entirely of room suites made up of large square and small rectangular rooms.  But what about kivas?  These round rooms are often considered one of the hallmarks of pueblo architecture, and while their function is disputed their presence is often thought of as near-universal.  Salmon complicates this picture considerably.

Great Kiva, Salmon Ruins

There were two round rooms in the Chacoan-period construction at Salmon (note these caveats; they’re important).  One was the great kiva in the plaza, a standard Chacoan form that presumably had ritual functions, and another was and elevated, blocked-in kiva at the center of the main roomblock that Salmon specialists refer to as the “Tower Kiva,” although it actually isn’t a tower kiva in the sense in which Chaco specialists use the term.  Both of these seem to have had important community-wide functions and they were probably not residential (though I’m less sure of this in the case of the Tower Kiva than in the case of the great kiva).  What Chacoan-period Salmon lacked, however, were the smaller kivas that are ubiquitous at Pueblo Bonito, Chetro Ketl, and other great houses at Chaco.  These are the kivas that Steve Lekson thinks were residential rather than ceremonial, although others disagree.  In any case, they don’t seem to have been part of the original plan for Salmon.

So what gives?  Well, if we buy Lekson’s theory, which I basically do, what seems to be going on here is that the residential functions filled by kivas elsewhere were filled by the large square rooms at Salmon.  As I noted in the previous post, the fact that some great houses have room suites with big square rooms while others have different types of suites with associated kivas suggests that there were two different residential patterns in the Chacoan system that might correspond to some important dimension of social complexity.  Salmon seems to support this idea, in that it apparently was designed (and occupied?) by one of these groups rather than the other, whereas at Pueblo Bonito, at least, both seem to have been present.

Kiva 121A, Salmon Ruin

If you’ve been to Salmon, this may seem a bit confusing, because one of the most obvious things you can see there is that there are plenty of kivas!  They’re built into the square roomblocks, just like at Chaco!  And, indeed, they are.  Excavation showed, however, that these kivas are not original to the building.  Instead, they were built into the large Chacoan rooms in the post-Chacoan period.  The Chacoan period at Salmon seems to have ended around 1125 or 1130, coincident with the end of major construction at Chaco and extensive evidence of major changes in the Chaco system that may or may not have constituted the “collapse” of that system.  The original idea the excavators had was that this involved the total abandonment of Salmon for a few decades, after which it was reoccupied by a new group with ties to the Mesa Verde region to the north which remained there until the site was abandoned completely in the 1280s or 1290s along with the whole region.  It later became clear that there was at least a small “Intermediate” occupation between the “Primary” (Chacoan) and “Secondary” (Mesa Verdean) occupations, and the CDA project has redefined these occupations to emphasize continuity between the last two, seeing them as “early” and “late” periods of a continuous local “San Juan” occupation as opposed to a migration from the north.

In any case, it was the “Secondary,” “Mesa Verdean,” or “San Juan” occupants, not the Chacoans, who built kivas into the Chacoan rooms.  Note that architecturally, these are not Chacoan kivas, which have a very standardized set of features, but instead more closely resemble Mesa Verde kivas and may reflect local architectural traditions such as the use of river cobbles rather than sandstone blocks in some contexts.  They were mostly built into the large square living rooms, although some were in the smaller rooms, which were also often subdivided with adobe walls to create spaces more typical of small sites in the area than the large rooms typical of Chacoan great houses.

Kiva at Salmon Ruin Showing Use of Cobble Masonry

The fact that these kivas were mostly built into the Chacoan living rooms is another point in favor of Lekson’s arguments that kivas were residential, especially since there’s some evidence from the Salmon excavation data that there was more continuity between the “Chacoan” and “San Juan” occupations than the excavators thought.  One interpretation for the construction of the kivas is that whoever was living at Salmon in the 1200s knew how the room suites had been used in the Chacoan era and wanted to continue to use them the same way but in a way that was consistent with local traditions and practices.  These people may or may not have been descended from the original inhabitants of the site.

The upshot of this is that we have strong evidence here that there was a practice in at least one Chacoan great house in the late 1000s and early 1100s of residential use of room suites focused on large square rooms facing the plaza.  It’s hard to tell if this pattern holds for any of the sites at Chaco itself (Hungo Pavi?), since the most extensively excavated ones were excavated long before the techniques that allowed the Salmon excavators to carefully differentiate between occupations were developed.  There is some evidence from the less extensive excavations at Pueblo Alto, however, which were done by the Chaco Project around the same time Salmon was being dug, that there was a similar pattern there of kivas being added to an original plan lacking them.  The kivas in the southeast corner of the Chetro Ketl plaza also seem to be very late, and the other parts of that site have relatively few kivas, most of them in elevated contexts similar to the “Tower Kiva” at Salmon.  Something similar may be true for the blocked-in kivas in the central roomblock at Pueblo del Arroyo.

Chacoan Masonry at Salmon Ruin

That leaves Pueblo Bonito.  The enormous complexity and early excavation of this site make teasing apart the different stages of construction enormously difficult, but one possibility is that at least some of the kivas there have a similar history to the ones at Salmon.  This may be particularly the case in the southwest corner, which has several kivas that may have been added into older square rooms and is also the area with the well-defined early room suites with large square rooms taking the place of kivas.  It’s also likely that many of the plaza kivas were very late additions like the ones at Chetro Ketl.  The blocked-in kivas in the southeast corner are trickier to interpret, and I’m not sure at this point if they represent something like the Salmon pattern or a different phenomenon entirely.

The excavations at Salmon resulted in a vast amount of information that is only now beginning to be incorporated into the study of the Chacoan system overall.  This evidence for residential use is just one example, but an important one, of how this data can lead to important insights not just about Salmon itself but about other parts of the Chaco world as well.

Central Roomblock at Salmon Ruin

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More Turkey Stuff

Rooms in Northwest Part of Salmon Ruin

In looking into recent research on Southwestern turkeys, I found an interesting paper from 2007 by E. Bradley Beacham and Stephen R. Durand about turkey eggshell.  Specifically, they came up with a new technique for analyzing archaeological eggshell to determine whether or not the egg had hatched.  The idea behind it, confirmed by an experiment they did with modern wild turkey eggs, is that bird embryos take the material to develop their skeletons from the interior portion of their eggshells, so the longer an embryo has been developing in the egg the more reduced the inside of the shell will be.  This is clearly apparent in microscopic examination of modern eggshells.  The usefulness of this technique is that it can theoretically determine if turkeys were being bred, as opposed to simply being kept captive, if large numbers of eggs had hatched.  Beacham and Durand connect this to a longstanding dispute in Southwestern archaeology over how to interpret the evidence of archaeological turkeys, with one side arguing that turkeys were introduced from Mexico as already domesticated animals, with the wild turkeys currently known in the Southwest possibly descending from escaped domesticated turkeys that went feral, and the other side arguing that turkeys were domesticated in the Southwest from local wild turkeys, possibly quite late after many years of having been captured in small numbers for their feathers but not bred.  We now know from genetic evidence that both of these theories are wrong, although the former is apparently closer to being true, and it now seems that turkeys were introduced as domesticated animals, probably from the east rather than the south, and that this happened quite early, at least by Basketmaker II and possibly during the Late Archaic.

The archaeological eggshells Beacham and Durand analyzed using this technique were from two rooms at Salmon Ruin, a major Chacoan outlier on the San Juan River near present-day Bloomfield, New Mexico.  These rooms were excavated in the 1970s, and they were selected for this analysis because they contained significant quantities of well-preserved turkey eggshell.  Eggshell is very fragile and needs very good preservation conditions to survive, so the excellent preservation conditions at Chacoan great houses like Salmon are important in doing this kind of research.  The sampled shell fragments came from strata clearly identified with the three originally designated periods of occupation at Salmon: Primary or Chacoan (ca. 1088 to 1125 AD), Intermediate (ca. 1125 to 1190), and Secondary or Mesa Verdean (ca. 1190 to 1280).  These turned out to have quite different results.  The Primary shells overwhelmingly showed no evidence of having hatched, and little evidence of having held embryos long enough for material to be taken from them at all.  The Intermediate shells, on the other hand, mostly did show evidence of having held embryos for significant periods, and about half of them seem to have hatched.  The Secondary shells, most of which came from a different room from the other two samples, were more like the Primary ones in that they showed little evidence of embryo development and almost none of hatching.

Salmon Ruins Sign

This is odd, and hard to interpret in terms of domestication or intensity of use.  The sheer amount of Secondary eggshell throughout the site, compared to the much smaller amount from earlier periods, suggests increased use of turkeys during the thirteenth century, which is consistent with evidence from throughout the Southwest showing increased turkey use, especially for meat, during this period.  The shell evidence, however, while it does show that breeding seems to have taken place during the Intermediate period, doesn’t really fit with this increased overall use.  It’s possible that this is simply due to a sampling issue, and that further study of a larger sample of Secondary eggshell would show more evidence for breeding.  It is also possible, as Beacham and Durand note, that this increased use of turkeys involved the consumption of eggs as well as meat, and that the Secondary sample analyzed is associated with this use of eggs rather than with breeding.  Something similar may also be going on with the Primary sample, although Beacham and Durand, who clearly seem to favor a late onset of breeding and domestication, prefer to see it more as evidence that turkeys were not yet fully domesticated at that time.  As noted above, however, the genetic evidence argues strongly against this interpretation.

Given the genetic evidence, it is not clear how to interpret the eggshell evidence in this paper, but it offers an interesting new way to look at turkey eggshell in well-preserved contexts, and give the frequency of these contexts in the Southwest further use of the technique may further refine our understanding of the issues surrounding turkey use in the prehistoric Southwest.

BEACHAM, E., & DURAND, S. (2007). Eggshell and the archaeological record: new insights into turkey husbandry in the American Southwest Journal of Archaeological Science, 34 (10), 1610-1621 DOI: 10.1016/j.jas.2006.11.015

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