http://www.nytimes.com/2009/06/30/science/30chaco.html?partner=rss&emc=rss
CASAS GRANDES, Mexico - From the sky, the Mound of the Cross at Paquimé, a 14th-century ruin in the Mexican state of Chihuahua, looks like a compass rose - the roundish emblem indicating the cardinal directions on a map. About 30 feet in diameter and molded from compacted earth and rock taken near the banks of the Casas Grandes River, the crisscross arms point to four circular platforms. They might as well be labeled N, S, E and W.
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Steve Lekson, shown at Chimney Rock, Colo., has a theory tying Casas Grandes to Chaco Canyon and Aztec Ruins.
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Stephen Lekson, via Associated Press
ALL IN A ROW The maze of earthen buildings in Mexico known as Casas Grandes, or Paquimé in a 1995 photo.
"It's a hell of a long way from here to Chaco," says Steve Lekson, an archaeologist from the University of Colorado, as he sights along the north-south spoke of the cross. Follow his gaze 400 miles north and you reach Chaco Canyon in northwestern New Mexico, a major cultural center occupied from about A.D. 900 to A.D. 1150 by the pueblo people known as Anasazi. Despite the distance, Dr. Lekson believes the two sites were linked by an ancient pattern of migration and a common set of religious beliefs.
But don't stop at Chaco. Continue about 60 miles northward along the same straight line and you come to another Anasazi center called Aztec Ruins. For Dr. Lekson the alignment must be more than a coincidence.
A decade ago in "The Chaco Meridian: Centers of Political Power in the Ancient Southwest," he argued that for centuries the Anasazi leaders, reckoning by the stars, aligned their principal settlements along this north-south axis - the 108th meridian of longitude. In an article this year for Archaeology magazine, he added two older ruins to the trajectory: Shabik'eschee, south of Chaco, and Sacred Ridge, north of Aztec. Each in its time was the regional focus of economic and political power, and each lies along the meridian. As one site was abandoned, because of drought, violence, environmental degradation - the reasons are obscure - the leaders led an exodus to a new location: sometimes north, sometimes south, but hewing as closely as they could to the 108th meridian.
"I think the reason is ideological," Dr. Lekson said on a recent visit to Paquimé. "The cultural response to something not working is to move north, and when that doesn't work you move south. And then you move north again and then you move south again, and then you finally say the hell with it, I'm out of here, and you go down to Chihuahua."
For many of Dr. Lekson's colleagues that is an awfully big leap. With all the ambiguities involved in interpreting patterns of dirt and rock - the Anasazi left no written history - archaeologists have been more comfortable focusing on a particular culture or a particular ruin. Dr. Lekson is constantly reaching - some say overreaching - to make connections between isolated islands of thought. Scheduled for publication this summer, his new book, "A History of the Ancient Southwest," will go even further, offering a kind of unified theory of the Native American population movements that have puzzled Southwest archaeologists for many years.
"Steve has definitely been the one who has dragged us kicking and screaming into 'big picture' archaeology," said William D. Lipe, emeritus professor of archaeology at Washington State University. "In many ways, Steve's ideas and publications have driven much of the intellectual agenda for Southwestern archaeology over the last 20 or more years." That does not mean, Dr. Lipe added, that he buys the idea of the Chaco meridian.
On a walk around Paquimé, Dr. Lekson points out his evidence. Casas Grandes, the Spanish name for the ruins, means "big houses," and the multistory structures remind him of the palatial "great houses" at Chaco and Aztec. Inside the structures, people moved from room to room through T-shaped passages like those at Anasazi sites. At the House of the Pillars, a row of three colonnades formed a grand entranceway. "No one around here had colonnades except at Chaco," Dr. Lekson says. A coincidence or a connection?
Paquimé also hints at other influences. Ball courts, used for ceremonial games, are typical of those found in southern Mexico and Central America. Effigy mounds, in which dirt was shaped to form birds and other figures, resemble those built long ago by Native Americans in the Ohio Valley. A long sinuous row of mud and stone called the Mound of the Serpent seems to undulate like a snake.
"This thing runs north and south," Dr. Lekson says. "I love it." He points toward a prominent hill on the horizon called Cerro de Moctezuma. Barely visible on its summit are the remains of a centuries-old stone watchtower. Nearby, he says, is another snakelike mound running north and south.
"It's not as easy to see," he says. "You have to believe it."
There is plenty of evidence that ancient Americans were keenly aware of the cardinal directions. Watch the night sky long enough and it becomes clear that there is one star that does not move while the others circle around it: the north star or Polaris. Motivated perhaps by this knowledge, some ceremonial structures at Chaco are aligned on north-south axes, and the earthen walls at Paquimé zig and zag as though, Dr. Lekson says, they were "laid out on giant graph paper or with the old children's toy Etch A Sketch." Throughout the Southwest, modern pueblo religions typically include four sacred mountains, one for each direction, and pueblo people tell stories of ancestors moving south because of bad things that happened in the north.
If these people had been "meridian compulsive," as Dr. Lekson puts it, they had the astronomical knowledge to plot and follow a long straight line. "Lining things up is not an issue," he says. "The question is why."
"Chaco Meridian" came with a warning: "This book is not for the faint of heart, or for neophytes. If you are a practicing Southwestern archaeologist with hypertension problems, stop. Read something safe." Few of Dr. Lekson's colleagues heeded the advice.
"Steve is possibly the best writer in Southwest archaeology," said David Phillips, curator of archaeology at the Maxwell Museum of Anthropology at the University of New Mexico. "Our academic writing has this inherent gift of taking something interesting and making it dull and boring. And Steve doesn't have that problem. He thinks outside the box, and the rest of us comb through his ideas."
"Having said all that," Dr. Phillips added, "I personally think that the Chaco meridian is a crock."
In a vivisection of the theory, available online, Dr. Phillips laid out his objections. To begin with, the meridian is not exactly a straight line: if you zoom in, there are deviations of a few miles. Dr. Phillips also noted overlaps in the chronology of the rise and fall of the settlements. For example, Aztec, depicted in Dr. Lekson's book as the last outpost before the southward migration, was still occupied when Paquimé began.
In a good-natured rejoinder, Dr. Lekson answered these and other points. It is no surprise, he said, that the meridian "wobbles." Driven by the north-south compulsion, the leaders "did the best they could, lacking chronometers and GPS." He also disagreed that the overlapping timeline was a problem: "If I were the High Panjandrum, I'd surely send a gang ahead to build a comfortable palace before I dragged my Royal Self over hill and dale to the new Pleasure Dome in Xanadu."
Debates like this can go on forever. Where the two archaeologists fundamentally disagree is over how a theory should be constructed. To Dr. Phillips, Dr. Lekson is arguing more like a lawyer than a scientist - marshaling corroborating evidence for what he already has decided is true.
"Anyone can take any position and find evidence," Dr. Phillips said. "Done properly, science means that you stop yourself and figure out what the opposite is - the null hypothesis - and you prove the null hypothesis couldn't possibly be true. By process of elimination, your desired outcome becomes more plausible. This gets back to Karl Popper. You can only falsify."
But Dr. Lekson insists that archaeology can advance only by pushing beyond the Popperian ideal, trying to make sense of all the data with plausible accounts of what was happening historically in the ancient Southwest.
"We were trained to treat ancient Pueblo societies like cultures in laboratory petri dishes," he recently wrote. "Sprinkle the right amount of rainfall on the proper soil and up popped pueblos." What has been neglected, he says, is an appreciation for the unquantifiable.
"Unless you understand the broad outlines of the story - the history," he says, - the questions you are asking could be pointless. "You may be answering them very, very nicely and staying close to the data and doing good conservative science, but you could be asking the wrong questions and wasting a lot of money and time doing it."
With its grand sweep, the new book, "History of the Ancient Southwest," is vintage Lekson, and there is no reason to think the book will be any less controversial than the meridian theory, which forms but one thread of the saga.
"Lots of people could do what I'm doing, but they are choosing not to," Dr. Lekson said late one afternoon at Paquimé. "It's professionally dangerous to some extent." As he cracked open a Tecate, he described his frustrations at the slow pace of the field.
"The Southwest is one of the most heavily studied archaeological regions in the world, bar none except maybe downtown Athens," he said. "Per square mile, probably more money and time and energy and thought have been invested than anywhere else. If we can't take a stab now and try to put everything together, we should probably just hang up our trowels and say, 'Let's quit. We're not learning anything. We're just spinning our wheels.' "
