A massive and rather cunning bison kill carried out some 2,500 years ago among the sand dunes of southern Alberta left behind a wealth of artifacts that are offering new insights into a poorly-understood culture of the ancient Northern Plains.

In addition to the scattered remains of at least 65 bison, archaeologists have found more than a hundred stone points, most of them fashioned from a type of rock found only in North Dakota, a thousand kilometers away.

And beneath the layer of animal fragments and tools, even more rare finds were discovered: eight arrangements of bison bones found standing on end, perched in precise, almost sculptural patterns.

Excavated between 2004 and 2012 in the Fincastle Grazing Reserve just north of the Montana border, the site has revealed a chapter in Plains history that was nearly lost, said Dr. Shawn Bubel, archaeologist at the University of Lethbridge.

“I started to excavate at Fincastle was because the site was being looted,” Bubel said.

“There was evidence of pits dug across the site, gouges in the side of the dunes, and bone was tossed everywhere.

“The Archaeological Survey [of Alberta] was notified of the situation, and together we came up with a plan to survey and document the site before it was lost.

“As it turned out, the project grew into something fantastic. The archaeological remains were incredible.”

The most abundant artifacts are more than 200,000 fragments of bison bone, comprising the remains of dozens of animals that were butchered and processed, likely in a single event.

Radiocarbon tests of several of these samples returned dates in the range of the year 500 BCE.

The location of the kill site suggests that the hunters used a particularly canny approach — ambushing the herd as it watered in marshy land tucked among the sand dunes, leaving the animals with few routes for escape.

“It’s not what most people think about when bison hunting is talked about,” Bubel said.

“Big bison-jump sites where the hunters drove the herd off a cliff, or used the natural landscape to drive the herd into a trap like an arroyo, or driving the bison into a trap they constructed to enclose the animals, are the main bison hunting strategies archaeologists talk about.

“Fincastle showcases more of a stalking and ambushing strategy.”

The only types of bone in short supply at the site were skulls, Bubel noted, which appeared to have been detached, either to harvest the brains — which were often boiled for use in hide-working — or for ceremonial purposes. [Discover another ancient hunting site: “Butchered Bones Found in Yukon Cave Bear Marks of Early Americans, Study Finds“]

Even more noteworthy, however, are 118 projectile points, whose styles and sizes suggest the influence of two major cultural complexes in the region.

Some of the points are broad-faced and side-notched, like those associated with the Besant Phase, a complex whose traces are more often found to the east, starting around 2,000 years ago.

But some of the tools are more elongated than typical Besant points, suggesting the distinctive style of a more distant group, the Sonota, which was based in what’s now the Dakotas.

“These points showcase attributes that are seen in [both] Besant and Sonota point assemblages,” Bubel said.

“What makes them of great interest is that they were made 2,500 years ago.

“The Fincastle assemblage is one of the earliest occurrences of this cultural group in the Northwest Great Plains — it confirms that the Besant/Sonota cultural groups were living in southern Alberta by that time.” [See another recent find of ancient stone points: “13,500-Year-Old Tool-Making Site Uncovered in Idaho Forest“]

The fact that these points were found in Alberta also raises questions about how — and how far — these cultural groups spread to the north and west.

“The points and tools were predominantly made of Knife River Flint that came from North Dakota,” Bubel explained.

“More than 75 percent of the tools were made of this stone.”

“Does this mean that hunters travelled from the Dakotas into Alberta? ” Bubel conjectured. “Perhaps.”

“One could also argue that the hunters were already in Alberta and simply traded with other groups living in the Dakotas for Knife River Flint.

“That could have been the case, but the quantity of Knife River Flint is very high in the Fincastle assembles — higher than what is normally seen if an exotic stone was traded in.”

For more clues as to who the ancient hunters were, Bubel and her team have also investigated the mysterious displays of standing bison bones found buried under the debris, rare formations known as bone uprights.

“The upright features are very rare,” she said.

While other sites have included bones stuck in the ground, they were typically put there to serve a certain function, like tying down a tipi flap, or securing hides for scraping, she said.

“But the uprights at Fincastle are not utilitarian.”

And yet, each of the eight uprights was clearly arranged in a deliberate pattern.

“The Fincastle uprights show intentional placement of particular bones into each feature,” Bubel said.

One upright, for examples, features a tibia, or lower leg bone, surrounded by four jaw bones, all set on end with the teeth facing outward.

Another showed three shoulder blades placed in the shape of a triangle.

“In all of the features, the bones were positioned in an upright way, and were pushed all the way into the ground so that they would not have been visible from the surface.

“Were they ceremonial offerings?”

Here, too, the archaeologists see possible clues to the hunter’s identities.

“Bone uprights have been noted at Sonota sites in the Dakotas,” Bubel said, “though these are different than those at Fincastle.” [Learn about another unusual site left by bison hunters: “Utah Cave Full of Children’s Moccasins Sheds Light on Little-Known Ancient Culture“]

Bubel and her colleagues intend to continue analyzing the traces left by the ancient hunters, in an effort to tease out who they were, and where they came from.

“I have my thoughts on this – that the Fincastle hunters have strong ties to the Dakotas, likely even travelled from there.

“But this remains a hypothesis, for now.”

Bubel reports her findings in the journal Plains Anthropologist.

Bubel, S. (2014). The Fincastle site: A Late Middle Prehistoric bison kill on the Northwestern Plains Plains Anthropologist, 59 (231), 207-240 DOI: 10.1179/2052546X14Y.0000000009