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Dig this!
Chimney Rock dig a sherd success
Wednesday, July 22, 2009

Take a 1,000-year-old, ancient Puebloan site that links to a major astronomical “capital” 100 miles away, combine it with archaeology connections to the University of Colorado spanning 40 years, and you end up with a masterpiece of excavation and mystery just a half-hour from Pagosa Springs.

The Chimney Rock Archaeology Area is best known locally as the towering pillars of stone that rise above the valley floor near the intersection of U.S. 160 and Colo. 151. Visible from areas in Pagosa Springs, the formations are just a small part of the site that has attracted attention from archaeologists both regionally and worldwide. In fact, a film crew from the National Geographic Society was at the site in late June to document the current project, which could provide conclusive evidence that Chimney Rock is not a stand-alone site, but part of a much larger group of ancient pueblos whose function is related to astronomical events.

Chimney Rock was designated an Archaeological Area and National Historic Site in 1970 and lies on 4,100 acres of San Juan National Forest land surrounded by the Southern Ute Indian Reservation. The site was discovered in the 1920s and major excavation and repair work was done in the 1960s by Dr. Frank Eddy of the University of Colorado. Chimney Rock Archaeological Area (CRAA) is under the care and protection of the USDA Forest Service and the Chimney Rock Interpretive Association (CRIA). Since 2008, the site has been on Colorado’s Most Endangered Places List and the CRIA has a staff of nearly 80 volunteers that conduct tours and ensure the site is well-cared for.

In 2009, federal funding and grant money was awarded to the USDA Forest Service for excavation work to stabilize walls of the Great House structure that was built near the top of the formation, adjacent to the large chimneys. The stabilization work provided an opportunity for excavation and a full-blown archaeological dig at the site that has been relatively untouched since work was done in the 1970s.

The excavation is being overseen by Dr. Steven Lekson at the University of Colorado, and according to Brenda Todd, the on-site leader, their part of the work will have several major goals: to find samples of wooden beams that are large enough to examine the tree rings to determine cutting dates of the timbers, as well as find pottery sherds that can be dated or localized using advanced techniques to determine the origin of the clay. Timber samples from previous excavations have determined two dates, A.D. 1076 and 1093, with both years being significant for major lunar standstill events.

Another goal of the dig is to examine wall construction techniques to provide more evidence that the Great House is indeed a direct export of the Chaco Canyon site in New Mexico and not simply a later copy.

One of the mysteries of the Chimney Rock site that current archaeologists hope to understand better is the evidence that the entire Great House was built quickly as one project, rather than enlarged gradually as a growing village might require, and was occupied for less than half a century. The thick walls are constructed with the same techniques used at Chaco Canyon and are beautifully and masterfully put together with a “core and veneer” technique that uses large stones for structure and smaller stones for fill and stabilization. The walls are built in straight lines and are two-sided, with a rubble core fill. Much of the current wall damage and buckling is occurring from earlier repairs using conventional mortar that is much heavier then the natural silt and clay used in the ancient build.

A week into the excavation, site archaeologists had removed most of the rubble of collapsed walls from the two rooms they were working on and were just at the level of where the original roof had collapsed from fire. The shovels were traded for small trowels and brushes for the tedious work of preserving any salvageable artifacts that they might find. Small patches of original plaster wall covering were beginning to be visible in the room interiors, and although badly disintegrated, the first burned timber was discernible in the dirt.

Excitement filled the two pits in early June when the first pottery sherd was discovered in the soil. The sherd had clear markings that were indicative of Chaco style and would be sent off to a lab for the clay to be examined. Although the first burned timber was only a starting point for the long weeks of slow digging ahead, site leader Brenda Todd was confident that the crew of all graduate students from the University of Colorado would find pieces that were preserved enough to offer at least 30 rings for dating and more importantly, pieces with outside rings that would determine cutting dates of the roof timbers.

Erin Baxter and Jakob Sedig are the two student archaeologists in charge of Room 5, and as Baxter explained, what is found beneath the burned timbers will be the most important. “The roof was burned,” she said, “which was pretty hard to do. The burning roof collapses, and the walls soon collapse inward on top of it. The room underneath the burned timber and collapsed walls is preserved.”

By the end of June, and nearing their July 3 deadline for excavation, the well-tanned crew had dug pits that are accessible by ladders and had reached the floor of the original rooms. In Room 7, archaeologists Allison Bredthauer and Kellam Throgmouton have discovered numerous burned beams and 150 to 200 charred corn cobs. Only a small handful of the cobs remained on the site, but Bredthauer proudly presented them for a photo. Several of the cobs were found with the corn husk intact and braided to each other, as if they had been hanging from the ceiling. Their biggest find, and one that was documented by the National Geographic Society, is an intact vessel found in a corner with corn cobs inside. Both Room 7 and 5 have original, intact plaster on the walls, although any paint that may have existed is long gone. Between both rooms, at least 30 good samples of wood were found that are large enough to date by tree rings.

In Room 5, Baxter and Sedig discovered no artifacts when they reached floor level, so they dug deeper. Below the 15 centimeter (about 6 inches) thick clay floor, the duo found animal bones, pottery sherds, a bi-face knife blade, and even a bear jaw. “Jakob (Sedig) is a good finder,” Baxter shared. He was able to pick out the intricate finds from the soil that had held them for almost 1,000 years. Exploring even deeper revealed interesting pits, most likely ancient fire rings, in the hard bedrock that is almost impossible to dig through without power equipment. Baxter believes that Room 5 was once outside of the Great House and when the room was built a new floor covered the bedrock features and artifacts that they found. In contrast, when Room 7 was excavated below floor level, no relics were revealed.

Todd noted that nearly all artifacts had been removed from the site and sent to various labs for testing. The tree samples will be dated at the University of Arizona, and as Todd explained, there was no shortage of labs volunteering to be a part of this amazing archaeological find. In addition to the intact vessel, many broken pots were found that can be reconstructed, and the corn cobs can be analyzed using modern techniques to determine where the corn was grown. According to the group, their biggest accomplishment was finding the perishables and the intact vessel, a “fortunate find” according to Todd. Once analyzed and studied, all artifacts from the site will be curated at the Anasazi Heritage Center in Dolores, Colo.

Although the excavation is the highlight of the project for the archaeologists, there is still much more work to be done. Jason Chuipka has been on site throughout the entire process and will remain at Chimney Rock long after the dig crew is gone. Chuipka not only is overseeing the stabilization project, which is the reason the dig happened in the first place, but is also in charge of the intense and systematic documentation of the construction techniques, previous repairs, newly-exposed walls, and thorough photographs of the entire process that will be compiled into a report that can be used by future teams. Chiupka will work throughout the rest of the summer and into the spring of 2010. Previously a working archaeologist for 12 years, Chuipka returned to school and now does contract mitigation work for companies and organizations that wish to have sites documented before they are destroyed or changed. The goal at the Chimney Rock site is long-term preservation.

For a project of this magnitude and importance, Todd hand-picked her crew from a group of graduate students who had previous field experience with other digs.

“This is not a field school,” she elaborated. “This is the real deal.” With their contractual obligation to reduce the fill in the excavated rooms fulfilled on July 3, the group will then begin the long task of documenting their project. For Todd, that means continuing to write her Ph.D. thesis that is partially based on Chimney Rock as an outlier of Chaco Canyon. As if to support the theory of a link between the two sites, the clouds lift and Huerfano Mesa, located in Northern New Mexico and a prominent feature in the northern Chaco basin, is visible in the distance. The same mesa is clearly visible from Chaco Canyon.

Although the special excavation and stabilization tours have ended, guided tours of the entire site will continue throughout the summer. For more information, call 883-5359, or visit ChimneyRockCO.org.