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Research, Scholarship and Creative Achievement at UTSA

Discovering History Along the River

“People were using that river area 10,000 years ago, and people are still using it today.”


Humans have lived along the San Antonio River for more than 10,000 years, according to evidence unearthed by University of Texas at San Antonio (UTSA) archaeologists.

Spear points, stone tools, charcoal and other prehistoric artifacts discovered during excavations in the area of the San Antonio River Improvements Project paint an illuminating picture of the continuum of human habitation along the river, said project archaeologist Kristi Ulrich, who led the dig in which the oldest artifact—a 10,480-year-old spear point—was found last year in Brackenridge Park. “It was one of those things where, as you pull things out, you see time going back farther and farther,” she said. “That people were using that river area as far back as 10,000 years ago and that people are still using it today as a recreation area is amazing.”

There’s a reason the signs of Paleo-Indian life are found by the water, Ulrich pointed out. “You have water, which you need to live. You have fish as a food source and pecan trees all over the area. It’s one of those areas where, if you had to find a place to live, this is where you would want to be. Also, they were getting the chert [flint] to make their stone tools from the river basin.”

Ulrich works in UTSA’s Center for Archaeological Research (CAR). Established in 1974, the center conducts research throughout Texas and beyond; performs excavations for local, state and federal agencies; trains students; and curates archaeological collections. It will curate the artifacts collected as well as related materials in perpetuity, CAR Director Steve A. Tomka said. “We have over 10 million artifacts. Some of them are from the National Park Service. Some are collections from federally funded projects. The majority are from projects funded by various state agencies.”

The artifacts are housed in CAR’s state-certified curation facility, one of only three such facilities in Texas affiliated with universities. UTSA researchers do not have equipment to radiocarbon date organic material and must send those samples to an outside lab. “We would love to have a radiocarbon dating laboratory here on campus,” Tomka said. “There are not that many across the country. Even better would be a mini nuclear research reactor with the capacity to do a much larger suite of cutting-edge analyses.”

Much of CAR’s work is contract archaeology having to do with construction of roads, which Tomka calls its “bread and butter.” But the center also has discovered the true location of the Acequía Madre, built between 1719 and 1721 to supply water to the Alamo’s fields. After the irrigation channel was buried in 1905, its location was lost. CAR was hired to locate it and its dam, and, after studying historical maps and aerial photos and digging a dozen trenches, they found them in front of the Witte Museum. Among the artifacts discovered during the excavation was a frying pan used during rattlesnake fry fundraisers in the early days of the Witte, Tomka said.

The chance to really dig into the area’s archaeology came with the San Antonio River Improvements Project, a multiagency effort that includes recreational amenities and ecosystem restoration along 13 miles of the river. SARIP sought a survey of the site before construction of a sidewalk system and lighting. It has given researchers an opportunity to work continuously on a long-term project, and they are learning more about life along the river through the millennia. The project has “allowed us now, for the first time in 30-odd years, to consistently approach archaeology along the river from up here all the way down to Wilson County, and that is really giving us a better perspective on how prehistorically life changed a lot at the river,” Tomka said. “It’s also giving us perspective into how life was in the 1700s, when the missions were established, all the way back to about 10,000, 12,000 years ago. This is the first time we’ve been able to do projects where we are discovering things that are 10,500 years old. We’ve never had anything quite that old because the archaeology didn’t go deep enough into the deposits.”

Completed several years ago, excavations on the Museum Reach yielded relatively few prehistoric artifacts by virtue of urban development. Most of the finds dated to the 1920s, including large quantities of beer bottles from area breweries. So far, about 5,000 artifacts have been collected during the project, ranging from stone-tool-making debris to snail shells to those ubiquitous beer bottles, Tomka said. Excavations continue along the more rural Mission Reach segment of the project. Eric Oksanen is project archaeologist for the current fieldwork being done, which is expected to continue through 2013. He said the sheer size of the excavation area is a rare opportunity for researchers who typically work within a much smaller swath of land. “I don’t know of any other study of a river system that will be this complete. This reach of the San Antonio River, more than anywhere else, will have a continuous record of the soils, underlying geology, archaeology and chronology of these dates.”

As of May, the Mission Reach fieldwork had yielded evidence of a 6,000- to 7,000-year period, with radiocarbon dates that place human occupation of the area from 600 to 6,000 years ago. And new finds can be revealed at any moment. “At one of the sites we stripped,” he said, “we found a spear point that is about 9,000 years old in the last 30 seconds we were there.” What’s more, Oksanen said he is finding well-preserved organic material, such as charcoal, which can be dated to provide a long-range view of changes in the Mission Reach area.

Researchers have found prehistoric signs of life along other water sources as well. While excavating an area near Cibolo Creek in Boerne which was going to be disturbed for a sewer line project, CAR archaeologists found knives, hide scrapers and woodworking tools ranging from 3,500 up to possibly 8,000 years old. Spear points found suggest that earlier occupants of the site on the banks of the creek had connections to the Lower Pecos, while more recent occupants—if 3,500 years ago can be so described— suggest connections to Central Texas, Tomka said. “When you compare the projectile points made in those two different zones, you will see the material is very different.” Two acres of the site have been preserved for use as a field school to train student archaeologists beginning in 2014.

The SARIP work has also benefited another ongoing project by allowing researchers to collect clay samples to compare to shards of pottery in order to learn more about pottery making in the South Texas missions. Part of the research has included making pottery with various clays gathered from around the region in order to compare them to vessel shards, Tomka said. Making the pottery allows researchers to find out which clays are suitable for making ceramics before sending off samples for testing. “We are trying to put the two together to understand who made pottery in the missions, when they were making it, and whether they were exchanging it among the different missions across Texas.”

Samples of the raw clays and shards of vessels found at missions will be sent off for specialized analysis of their mineral composition. Any matches will help answer the question of where natives gathered the clay for making pottery. “That will point us to which tribes might have been the ones who made pottery and whether it was just one group who made pottery and distributed it with Spanish help throughout all the missions or whether people in different missions had their own sources of clay nearby,” Tomka said. “The same pottery shows up from El Paso to Espíritu Santo in Goliad and even East Texas. This has implications as to how the native cultures changed.”

Mission life meant learning new skills and practices for the native hunter-gatherers. “They start to learn agriculture; they start building irrigation ditches so the Spanish can irrigate the mission fields; they start shifting from stone tools to metal tools. All of these things changed their lives in very significant ways, and ceramics is one of these things. Many of them didn’t make ceramics, and then suddenly they were forced to either learn to make or to acquire ceramics and cook in and eat out of ceramic bowls that they didn’t have before,” Tomka said. “The ultimate thing we are trying to understand is how their identity was changing over time as a result of the Spanish influence.”

While South Texas mission ceramics might seem like a very specific area of study, it underscores a larger point: Understanding how people adapt to the changes in their world is not a quick process. The researchers at CAR are on the case, digging up answers to these questions piece by piece.

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