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Wednesday, Oct. 12, 2005 08:28 pm

A day at Bison Beach

Archaeologists uncover the first evidence of an aboriginal bison kill in Illinois

Alan Harn, archaeologist at the Dickson Mounds Museum, carefully excavates two ribs potentially belonging to Bison No. 8.
The e-mailed invitation from Alan Harn, archaeologist at the Dickson Mounds Museum, is succinct and inviting: “Temperature and weather tomorrow look good for a day of bison snooping on the beach.” No question, this site on the Illinois River south of Peoria is generating major excitement, and the discoveries being unearthed there are big news in the scientific community. What isn’t clear to me is why. What I am about to learn is a fascinating story of ancient bones complete with plot twists, near-misses, and more than one climax. After four-wheeling over uneven terrain, Harn and I start the morning with a visual survey of the rubble-strewn beach. We walk along the shore, heads bent, concentrating on each scrap of debris. I see nothing of note, but Harn sees plenty. Here are angular-edged stones that had been split by fire, indicating use in an ancient cooking process. Another sliver is a waste flake of stone chipped away during the crafting of a projectile point. And these dark bits? Charred seeds from prehistoric meals. Harn tells me of other items found on this beach: musket balls and an American long-rifle trigger guard, most likely from the 18th century. All of these items have been carefully documented and filed away like chapters in the extensive history of this beach, which begins with occupation by early Americans before 2000 BC. Fascinating though these finds and their underlying histories may be, they are not what we are searching for. We hope to find bones — bison bones. The already discovered skeletal remains of these creatures are responsible for the excitement surrounding the site. As crazy as it seems to hope that more bones will present themselves with no effort on our part, that is exactly what happened to start the furor back in 1995.
Because of a lack of time and funding, archaeologists rely heavily on the general public and serendipity to assist them in making discoveries. Harn tells me how Rick Scott, an amateur archaeologist, was walking this shore one day when he noticed animal bones protruding from the sediment. Realizing their possible significance, he turned them over to the Dickson Mounds Museum. The remains of eight bison, two elk, and two deer, along with prehistoric human artifacts, were subsequently unearthed. Still, I don’t quite get it: Yes, the bones were old and there were lots of them, but why the unusual amount of attention? I haven’t heard the whole story yet.
Bison bones are rarely found in Illinois, and this site was the first in the state to produce the articulated remains of several animals. Scientific reports have mainly noted bison bones in the form of tools and ornaments — most likely trade items — and food remains from later history. In short, all previous finds have pointed to a brief existence of bison in Illinois beginning in the mid-1500s and lasting until their extirpation in 1830. At least this had been the thinking before radiocarbon-dating results for bone samples from this site returned from the lab.
One of the samples yielded a date of about 1515 A.D. — just as one would expect, because bison were thought to have made their appearance in Illinois around 1450 A.D. The second sample, however, offered up a date from the fourth century B.C.! Could this be right? If these results were valid, bison had been on the Illinois scene 1,700 years earlier than had been previously thought. Additional samples were sent for confirmation. There was no mistake: Four of the five sample dates ranged from 265 B.C. to 365 B.C. Also supporting these dates was a geomorphological analysis of the site suggesting that the shoreline sediment from which some of the bison remains were eroding had developed about 2,000 years ago, placing them within the early time frame. This was an exciting story, to be sure, but for the archaeologists of the Illinois State Museum and its Dickson Mounds Museum branch, it was just the grab-your-attention first chapter. It was not enough for them to know that these were bones of an antiquity defying all previous knowledge of bison in Illinois. How did they come to be here? What story made the most sense? The bones were studied and scenarios considered. The researchers could find no evidence of human involvement in the animals’ demise. “We propose that bison skeletons and skeletal parts were deposited along the Illinois River shoreline as a result of accidental deaths in the river, perhaps due to falling through weak ice,” came the first proposal in a January 2000 report. It was a valid interpretation. This type of drowning incident had been documented by early explorers and seemed quite plausible. But still the archaeologists hoped for more. They hoped that maybe, just maybe, the site still held evidence that early Indian populations had made use of the bison.
Then came the summer of 2005. It was thought that remains might still be submerged because the modern river level is known to be 6 feet higher than it would have been at the time of the bison. After a spring- and summer-long drought, the archaeologists were presented with their first extended period of low water levels. But high expectations soon turned into disappointment when, on the last day of excavation, the researchers were forced to face the fact that they had found no direct evidence of man’s interaction with the animals. They returned the next day to close out the site only to find that the river had dropped dramatically from the day before. Laid out before them were a rib, a scapula, a patella, and a vertebra. Further excavation revealed the most complete bison skeleton found to date. Then, as they were liberating the bones from their resting place, they found it — a stone spear point embedded between ribs.
Projectile points are distinct in style among populations and time periods, like the fingerprint of a collective people. The point the archaeologists had found was of a type used from about the fourth century B.C. to around the time of Christ — a date compatible with the four early radiocarbon dates from the site. Later laboratory examination would reveal “impact cuts” that most likely resulted from spearing, as well as alterations of the bones that might prove to be butchering marks. The archaeologists had been hoping to find refuse pits or cooking facilities that would indicate that bison were regularly hunted in Illinois before 1500 A.D. They had never expected this. Bison No. 8 will now forever be known as the first evidence of an aboriginal bison kill in Illinois. The river has now reclaimed most of the Bison No. 8 site, and three sticks protrude from the water to indicate the excavated locations of various parts. At the water’s edge, however, an empty depression from which the skull has been removed is still visible. Harn picks up a shovel and begins restoring the shoreline to its former state, as required by a preexcavation agreement. I watch briefly as the outline of the skull begins to disappear before turning my attention to my own task. Harn has given me a metal probe to sink into the ground in the hope that I will strike something hard. Sinking the probe, pulling it back out, and moving a short distance (“You can be 1 centimeter off and miss something,” he warned), I was ever hopeful that more bones were just beneath my feet. When Harn finishes his shoveling, he takes over the probe and almost immediately hits something. Once again he grabs his shovel and begins to carefully peel away the layers. As with the previous finds, he doesn’t have far to go — about 8 inches down. He has nevertheless reached an undisturbed region, as indicated by areas where silty dark sediment has replaced decayed tree roots. This means we’ve gone below any recent alluvium and reached a natural, undisturbed clay surface. Now at a level close to the solid barrier to our probe, Harn arms himself with a trowel and cautiously skims closer to the emerging artifact. It is bone. He hands me a grapefruit knife with which to flick away the packed mud. We have found more ribs, most likely belonging to bison No. 8. We work diligently to smooth the sides of the pit and clear the mud from the ribs without making damaging contact with them. Finally the ribs are laid out in a presentation worthy of their importance. “If these bones date similarly, we are the first to lay eyes on them in 2,300 years,” says Harn. I stop my flicking and sit back on my heels, contemplating this thought. Suddenly I feel as if I’ve taken my proper place in the earth’s story — a speck of life, nothing more than the latest being to spend time on the banks of this river. I understand now why this place is so important.

An archaeologist’s excavation uncovers more than artifacts and bones. With the help of science and imagination, these discoveries turn into moments frozen in time through which archaeologists may reconstruct stories, build scenarios about relationships between ancient landscapes and ancient people, and ultimately make better sense of today through an understanding of yesterday. Once in a while, this frozen moment changes what we thought we knew. The information being gathered here is unprecedented in explaining the movement of ancient bison and the subsistence patterns of ancient peoples in Illinois.
“There is always something new to learn,” Harn tells me, his excitement contagious. And there are so many more questions to be answered now: Why haven’t bison remains from this earlier time period been showing up in refuse pits? Had hunting patterns changed? Was there something special about this particular location that made the animals more accessible? Was it perhaps a shallow-water crossing, a point where a hunter could lie in wait? If funding allows, the archaeologists are eager to expand their search of this site. Perhaps they are just a trowel scoop and a grapefruit knife flick away from continuing the story.


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