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Archive for November, 2010

Mix of Covered and Backfilled Rooms in Old Bonito

My main area of expertise when it comes to archaeology is the Southwest, but I currently live in New Jersey, and while I don’t know a whole lot about the archaeology of this part of the country I feel like I should probably weigh in on those rare occasions when an archaeological issue makes it into the news.  We seem to be in the midst of one of those occasions now, with the State Capitol Joint Management Commission having recently approved an order by Lieutenant Governor Kim Guadagno to rebury the Petty’s Run archaeological site, which is immediately adjacent to the Statehouse in Trenton.  This site, which was uncovered in 2008, contains a variety of buildings from the eighteenth and nineteenth centuries that shed considerable light on the early history of Trenton.  The site lies right between the Statehouse and the Old Barracks Museum, and the administration of then-governor John Corzine planned to make it a key part of a new state park.  The plan for establishing the park called for the site to be enclosed in glass, presumably to protect it while leaving it visible.

Room 6, Pueblo Bonito

When Chris Christie defeated Corzine last year, however, plans for the new park came to a halt and the site has just been sitting there, exposed but visible behind a fence.  Indeed, Guadagno’s problem appears to have been that the site is all too visible.  She can see it from her office in the Statehouse and she apparently considers it an “eyesore,” which is why she wants it reburied.  Many people, including political opponents of the Christie administration and Old Barracks Museum director Richard Patterson, are outraged by this move.  (The archaeologist who excavated the site, Richard Hunter, has declined to comment on the issue.)  Guadagno’s apparent motivation in having the site reburied does seem rather petty, but a lot of the outrage seems to be directed at the very idea of reburying the site.  I think this outrage is misplaced.  This may be a silly reason to rebury a site, but reburying (or “backfilling”) sites is a standard and very effective way of preserving them.

Chaco Preservation Crew at Work on the Fort Site

One of the major problems with excavation, and one of the reasons it is often avoided when possible, is that once a site is excavated it is no longer protected by the dirt that covered and preserved whatever was in it.  If left open a site will rapidly begin to deteriorate, so whatever organization is responsible for the site has a choice.  It can leave the site open and let it fall apart (not a popular option), or it can do something to preserve it.  In places like Chaco Canyon, where the visual impact of sites is considered a high priority, preservation involves an elaborate and very expensive effort at stabilizing standing walls and preventing further deterioration.  Since the main sources of impacts are weather and visitation, and these are ongoing year after year, preservation through stabilization means continual work.

Structure Covering Megalithic House, Mesa Verde

Another option is to build some sort of structure over the site to protect it from impacts while still leaving it visible to visitors.  In the Southwest this is rarely done for major sites because it makes them look “inauthentic,” with some exceptions such as Casa Grande and some of the especially well-preserved rooms at Pueblo Bonito.  For smaller sites and particularly fragile ones, however, this is a popular option, as it is much cheaper and less labor-intensive than constantly struggling to prop up the walls and generally provides better protection as well.  Many of the mesa-top sites at Mesa Verde and other parts of southwestern Colorado and southeastern Utah have this kind of protection.  It sounds like this is the kind of thing the Corzine administration was planning to do with Petty’s Run, although it’s not totally clear to me exactly how the glass enclosure concept would have worked.

Backfilling Using Tarps at Homol'ovi I

The final option, which is generally both cheaper and more protective than the other two, is backfilling.  This takes most or all of the site out of public view, of course, which makes it problematic for sites that are intended to be developed as tourist attractions.  For sites that are not publicly accessible, however, this is the standard means of preservation.  It can be done in a way that makes it relatively easy to open up the site again later for further excavation, and in many cases archaeologists will refill sites at the end of each excavation season with the intent of returning to them later.  This can be done with tarps, for example, as the Arizona State Museum has done in its multi-year research project at the now-closed Homol’ovi Ruins State Park in Winslow.  In some cases responsible organizations start out trying to stabilize excavated sites and end up backfilling them when they can no longer afford to.  This is what has happened at Casa Malpais, which is owned by the town of Springerville, Arizona.  Some rooms that had been left open after excavation were recently backfilled because the town could no longer afford to stabilize them.

Preparations for Backfilling a Room, Casa Malpais, Springerville, Arizona

Now, this is all based on my experience of preservation techniques at sites in the Southwest, and it’s certainly possible that archaeologists in the Northeast don’t do things the same way.  For one thing, Northeastern archaeology seems to be much more focused on the historic than the prehistoric period, presumably because there has been so much historic development overlying whatever prehistoric sites remain.  Since historic sites are often built of sturdier materials than those that were available to prehistoric people, it might not be as problematic to leave a typical historic site exposed as it would be to do the same with a typical prehistoric site.  On the other hand, preservation conditions are much worse in this humid environment than in the arid Southwest.  Water is one of the biggest threats to preservation of exposed sites, and with the amount of precipitation that is typical of this area I’m sure even the best-constructed historic sites are at considerable risk.  The fact that the Corzine administration’s park plan called for enclosing the Petty’s Run site in glass makes me think this is indeed a major concern in Northeastern archaeology.

Structure Covering Coombs Village, Anasazi State Park, Boulder, Utah

The upshot of all this is that to the extent that the Christie administration is showing a lack of respect for the state’s heritage in its treatment of the Petty’s Run site, that’s being manifested in the decision not to pursue the park plan rather than the decision to backfill the site.  Guadagno may be motivated by superficial aesthetic considerations in wanting the site reburied, but whether or not the site is an eyesore leaving it exposed is not the way to preserve it.

Highly Deteriorated Vertical Intramural Beams at Pueblo Bonito

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Turquoise-Encrusted Cow Skull, Santa Fe, New Mexico

In 1527 an expedition led by the Spanish nobleman Pánfilo de Narváez left Spain with the intention of conquering and colonizing Florida.  Accompanying the expedition as treasurer was Álvar Núñez Cabeza de Vaca, who ended up being one of a handful of survivors of the disastrous expedition.  Cabeza de Vaca later wrote an account of the expedition and the years it took for him and the other survivors to make their way from Galveston Island, where they had been shipwrecked after a series of disasters in Florida itself, to Culiacán in what is now the state of Sinaloa in western Mexico, where in 1536 they finally encountered other Spaniards who were busy conquering that area.  This account has become a classic of the ethnohistoric literature, both because Cabeza de Vaca was an unusually perceptive observer of the various native peoples he encountered during his travels and because very little other information is available about those peoples, whose numbers and cultures were later devastated by permanent European settlement so quickly and thoroughly that few observations about them were published.

One of the interesting episodes described by Cabeza de Vaca occurred when the small group of Spaniards arrived at a village where the inhabitants gave one of his companions a large copper bell decorated with a face.  When the Spanish, who were always very interested in any metals they could find, asked where it had come from the people told them they had acquired it from a neighboring group and that it had come originally from the north, where there was abundant copper.  At the next village the group visited they showed the people the bell, and were told that there was indeed much more copper where it had come from, in the form of both bells and plates, and that there were permanent dwellings in that area.  Cabeza de Vaca apparently concluded that the copper had come from the Pacific coast, which was indeed a major area of copper production in Mesoamerica.  This particular bell, however, and the other copper objects mentioned by the people he spoke to in the villages he visited probably did not come from West Mexico.

Macaw Feathers and Copper Bell on Display at Chaco Visitor Center Museum

This episode has been of considerable interest to archaeologists, as copper bells were among the most important items of trade between Mesoamerica, especially West Mexico, and the Greater Southwest.  They have been found in considerable numbers at Chaco Canyon, as well as at Hohokam and Sinagua sites in Arizona and various other parts of the Southwest.  One archaeologist, Jeremiah Epstein of the University of Texas, published an article in 1991 looking carefully at Cabeza de Vaca’s account and correlating it with known archaeological evidence and other ethnohistorical sources from later Spanish expeditions.  He concluded that it the likely source of the bell mentioned by Cabeza de Vaca, as well as other copper objects mentioned by the Ibarra expedition in 1565 and the Rodríguez-Chamuscado expedition in 1581, was the well-known site of Casas Grandes in northern Chihuahua.

The exact route of Cabeza de Vaca’s travels has been a matter of considerable debate.  Epstein’s article relied on a reconstruction of the route that placed the copper bell episode near the modern city of Monclova, in the state of Coahuila in northeastern Mexico.  This is about 500 miles southeast of Casas Grandes, which fits well with the claim that the bell Cabeza de Vaca mentions came from the north.  In addition, the Ibarra expedition visited the immediate area of Casas Grandes and reported copper ornaments among the local population there, and the Rodríguez-Chamuscado expedition encountered copper objects among groups in the Rio Grande valley east of Casas Grandes who reported that they came from the west.  Epstein concluded from these reports that Casas Grandes is the most likely source for the copper objects of the archaeological sites in the Greater Southwest known to have had large numbers of copper bells.  Furthermore, Epstein noted that while many Southwestern archaeological sites had copper bells, very few had bells in decorated with human faces, which Cabeza de Vaca clearly stated to be a characteristic of the bell he described.  Casas Grandes did have this type of bell, and it also had a variety of flat copper artifacts that could be plausibly described as the “plates” mentioned by the second village Cabeza de Vaca described.  (Interestingly, such “plates” seem to be virtually restricted to Casas Grandes in the Southwest, although copper bells are pretty common.  The only possible example of a flat copper artifact like this at another site was found in Room 2 of Pueblo Bonito.)  I find his specific reasoning about each line of evidence a bit less solid than he did, but all together I think he was probably right to point to Casas Grandes as the most likely source for the copper artifacts described by the sixteenth-century Spanish sources.

Doorway into Room 2 from Room 36, Pueblo Bonito

The most interesting thing about this, as Epstein noted in his article, is that Casas Grandes had been abandoned for about a century when Cabeza de Vaca came through the area and saw the bell that apparently came from there.  When it was occupied, Casas Grandes was one of the largest and most important sites in the whole region, and excavations there have shown that it was a major center for a variety of Mesoamerican-derived activities, including macaw breeding and copper working.  The bells and other copper artifacts found there were apparently made there, in contrast to those found at Chaco, which was occupied significantly earlier and imported its copper bells from West Mexico, which at that time was the only part of Mesoamerica to practice copper working.  By the late Postclassic period, however, when Casas Grandes flourished, copper metallurgy had become a standard practice at major centers throughout the Mesoamerican culture area.

In the sixteenth century, however, Casas Grandes was very clearly no longer occupied.  The Ibarra expedition, which came through the area in 1565, found the site already a ruin, and the only local people were hunter-gatherers living in simple, impermanent dwellings quite different from the imposing multi-story adobe edifices at Casas Grandes.  These hunter-gatherers, however, did have some copper “plates” which parallel the ones reported by Cabeza de Vaca’s sources.  The expedition also noted evidence of metalworking at the ruins of Casas Grandes, but did not mention any evidence that the current inhabitants had made their copper plates themselves.

So how did the hunter-gatherers who lived around Casas Grandes in 1565 get their copper plates, and how did the people in Coahuila in the 1530s and the people living along the Rio Grande in 1581 get their copper bells?  Epstein’s answer, which I find quite convincing, is that the local hunter-gatherers dug into the ruins to get the copper artifacts in them, then traded them to various other groups in northern Mexico.  That is to say, they “looted” the site for economic gain much the way modern pothunters in the Southwest and elsewhere do.  Indeed, according to Epstein, the extensive excavations at Casas Grandes conducted by Charles Di Peso for the Amerind Foundation in the 1970s uncovered “evidence of Precolumbian vandalism” (in Epstein’s words) in some areas of the site.  So it seems looting of archaeological sites has a long history in the Southwest.

Jerome, Arizona from Tuzigoot National Monument

What I find most interesting about this is the parallel to the situation in modern cities, which now contain such huge amounts of certain materials, especially copper, that they are becoming a major source for materials that have traditionally been mined from nonrenewable natural deposits such as those that spurred the settlement of Western mining towns like Jerome, ArizonaJohn Fernandez of MIT discusses this issue, drawing on the work of Tom Graedel at Yale, in this video from 2007 (starting at about 21:29).

Fernandez quotes Jane Jacobs as saying that “our cities are the mines of the future.”  And, at least as Fernandez presents it, that does indeed seem like a prescient statement.  Epstein’s article, however, demonstrates that digging for copper in abandoned homes is hardly a new phenomenon.  Like so much else that humans do today, it has a very long history.  The cities of today may be the mines of the future, but the cities of yesterday have already become the mines of the past.
ResearchBlogging.org
Epstein, J. (1991). Cabeza de Vaca and the Sixteenth-Century Copper Trade in Northern Mexico American Antiquity, 56 (3) DOI: 10.2307/280896

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