Nearly 1,400 years ago, a member of a nomadic people sheltering in the sandstone recesses of Pictograph Cave discarded a basket woven with willow and milkweed fiber.
It was a masterful construction that James Adovasio, professor of anthropology at Mercyhurst College in Pennsylvania, described as “closely coiled and the stitches so tightly packed that the basket would have easily held water.”
Adovasio, a leading expert in prehistoric perishable artifacts, was asked to examine the basket fragment — which in photographs resembles a cob of corn — by the Montana Parks Department, guardian of Pictograph Caves about six miles southeast of Billings.
Housed at the University of Montana in Missoula, the basket piece is among more than 30,000 artifacts recovered in excavation of the complex of three caves by the Depression-era Works Progress Administration between 1937 and 1941. For much of the time since, the collection has been boxed in the basement of the university’s Anthropology Department.
Under the leadership of state Parks Department archaeologist Sara Scott, the collection is getting renewed attention. A graduate student has been hired to catalogue and organize the artifacts — a process that has already paid off with the rediscovery of two 1-inch bone effigies that were presumed lost. One of the effigies represents a turtle, the other a human face.
“I’m really excited about what Sara is doing here,” said John Douglas, chairman of UM’s Anthropology Department. Pictograph Cave “is the most important prehistoric site in Montana.”
In the process of re-examining the collection, Scott contacted Adovasio, who happened to be in Montana at the time. He eagerly agreed to take a look at the basket fragment.
“I’ve seen every basket fragment found in an archaeological context in the West, but the specimen from Pictograph Cave is not one I have had the pleasure to examine,” he told the Montana scientists.
After viewing the artifact, he concluded that it “is a wall fragment of a basket that was most likely used as a tray by prehistoric people to parch seeds, separating the husk from the seeds so that they could be eaten.”
In a telephone interview, Adovasio said these early Americans would have placed seeds in the tray with small pieces of charcoal and continually flipped them to heat the seeds but not burn the basket.
“When they are parched like that, the seeds are more easily digestible,” he said.
Even then it was an old technique — one commonly used in the Great Basin area of Utah, southern Wyoming and parts of Colorado, Idaho and Nevada. The basket itself resembles those associated with the Freemont Culture, which flourished in the eastern Great Basin at roughly the same time, Adovasio said.
“One of the interesting mysteries of the Freemont is we don’t know how far they wandered,” he said. “One theory is that when the Freemont starts to fade, one point of exit might have been north.”
There’s no way to tell whether the people who left the basket at Pictograph Cave were part of a Freemont diaspora or if they simply obtained the basket through trade. Possibly the weaving technique was passed to each culture by a common ancestor in more ancient times, he said.
With permission from UM, Scott carefully shaved a tiny sample from the basket and from a willow “tinder stick” found in nearby Ghost Cave. Both caves are now included in Pictograph Cave State Park, along with Middle Cave, which produced little evidence of prehistoric occupation. Adovasio sent both pieces to Oxford University in Great Britain for a special type of radiocarbon dating called accelerator mass spectrometry. This technique can date materials using minute samples, Scott said.
Results show the basket was made 1,371 years ago, plus or minus 31 years, and the tinder stick, a fire-making tool that looks like the head of a mop, was 957 years old, plus or minus 27 years.
Although the excavations of Pictograph and Ghost caves 70 years ago were used by archaeologist William Mulloy of the University of Chicago to develop a prehistoric chronology for the northwestern plains, carbon dating techniques had not been developed at the time. The basket fragment and tinder stick, among the few items with a datable organic origin, are the first carbon dates from the Pictograph Caves artifacts collection.
Artifacts made of perishable materials are rarities in Montana archaeological sites, but Pictograph and Ghost caves are dry environments conducive to preservation, Scott said.
“Only two other sites in Montana produced basketry fragments and both are located in Carbon County,” she said.
The basket fragment and tinder stick were found among the top layers during the excavation process, which took archaeologists down 20 feet into deposits compiled over thousands of years of human occupation. Mulloy used projectile point types and stone tools to establish the earliest dates at 9,000 years ago.
Perishable material did not survive in the oldest layers, although the excavators identified hearths at various levels. But before carbon dating developed, charcoal would not have been considered valuable and was probably discarded, Scott said.
The caves were a tableau of pre-Columbian artwork. Several years back, a pictograph of an elk was dated to 2,145 years ago. Most remaining pictographs are barely visible.
In his doctoral dissertation in the 1950s, Mulloy explained the attractions of the caves that nature carved out of eagle sandstone south of the Yellowstone River. Pictograph Cave has a southwest exposure to the afternoon sun in winter, keeping it warmer than the surrounding area, he wrote. Bitter Creek, small and seasonal, was nearby and flanked by cottonwood that meant firewood would have been accessible. A variety of animals would have been available to feed travelers who either stayed in the cave or camped in the surrounding area.
It would be nearly impossible to identify the people who would have used the basket and tinder stick 1,400 to 1,000 years ago, Douglas said. They would have preceded the historic tribes of the region — the Crow, Cheyenne and Sioux who were living further east at the time.
“You’re talking about people who were very adept at using their environment,” he said. “They were using the bow and arrow, which was introduced about 1,500 years ago.”
Dried skins of prairie potatoes, other root plants, berries and seed helped supplement a diet of a variety of animals that ranged from rabbits to bison. While the importance of bison in their diet is debatable, bison bones are amply represented in the artifacts found in the caves.
“Native Americans living at Pictograph Caves 1,000 years ago likely focused a lot of their travel along the Yellowstone River corridor,” said Douglas MacDonald, an assistant professor in UM’s Anthropology Department.
But they traded and socialized throughout the Northern Plains and the Rocky Mountains, he said. Artifacts include tools made from stone collected throughout the region, as well as shell ornaments from coastal areas.
“Widespread kinship networks are important to hunter-gatherers for a variety of reasons, including trade, economy and social reasons,” MacDonald explained. “So, at times, individuals and families may have traveled widely to visit friends and family in other areas of the Plains (and) Rockies, but for the most part spent most of their daily lives in a core area along the Yellowstone River and vicinity.”
The size of groups visiting the caves would probably vary according to the reason for travel, he said. If socializing, they might have been moving in small family groups. If they were hunting deer or other prey, or were collecting roots and berries, small groups would also travel together.
But if they were after bison, larger groups may have gathered to hunt the massive herds migrating through the area.
While most artifacts from excavations at the caves are stored at UM, replicas of some are on display at the new Pictograph Cave visitor center, said Doug Habermann at the FWP office in Billings.
“You don’t want artifacts here unless you can secure them,” he said.
The park facility is not a museum and does not have a full-time staff or specialized curators to care for the valuable and rare items found in the caves, he said. But he hopes that Scott’s efforts will result in a database that the public can access.
Fall hours are now in effect at Pictograph Caves. The visitor center is open 10 a.m. to 5 p.m., Wednesday through Sunday.
Now that access to the collection has been opened and efforts are being made to put it in order for future research, Scott said she hopes students and scientists will take advantage of opportunities for further study. She can envision masters’ theses and doctoral dissertations for years to come.