The "stemmed points" found in two cylindrical pits at Nipéhe (Cooper's Ferry), Idaho, which date to around 16,000 years before the present
No matter who you are, your family left somewhere else to arrive here in America. And that’s always been one of our key ingredients. We’re the place so many have come for a shot at something better, from the very beginning, and this still goes on unabated right now.
The earliest coherent story of this kind that we know of has been taking shape over the last couple of decades or so at a site in western Idaho called Nipéhe (Cooper's Ferry), and it’s finally been solidified by more-convincing dating. We learn from this dating that a group of migrants arrived about 16,000 years ago, prior to the opening of any ice-free corridor. They must have come down the coast, on the water for at least some of the trip, around the glaciers, then taken a left turn at the Columbia River, and come inland.
But this isn’t just any old group. Their descendants, numbering about 3,500, are still in the same area today. They’ve historically called themselves Nimiipuu, but are also OK with the name most outsiders know them by: Nez Perce.
They brought techniques with them for crafting spear tips, or more properly “stemmed points”, that appear very similar to those found a bit earlier in Northeast Asia, especially northern Japan. What is significant is that the location of the tips, within two small purposefully dug cylindrical pits, has now been more directly dated, and it matches earlier indirect inferences about the site. This report, led by Loren Davis at Oregon State University, came out December 23 in Science Advances. There’s also a nice summary of the work in the December 23 issue of Science.
It had been thought for a long time that humans first got here over land, through an ice-free corridor between the Laurentide (eastern) and Cordilleran (western) ice sheets. That gap finally opened up completely around 14,800 years ago:
The ice-free corridor through present-day Canada opened up around 12,500 carbon-14 years, or about 14,800 calendar years, ago. Therefore, artifacts associated with humans from 15,000 or more calendar years ago makes the land-bridge hypothesis untenable. The various markers shown are radiocarbon data points that date to around this time
You’ve no doubt heard about the “land bridge” that once existed between present-day Siberia and Alaska, forming a region called Beringia, and that part was certainly easy enough to cross, but then you ran into massive glaciers, and you were not getting past those:
The land mass of Beringia 21,000 years before the present (dark green), contrasted with shorelines of today (light green). Glacial masses are shown in white. I’d migrate the hell out of here the first chance I got, too!
Over the last several years, evidence has been accumulating that suggests humans first settled North America from Beringia before the ice-free corridor opened up, by skirting the coast and arriving by boat.
A lot of that evidence is isolated and circumstantial, though, like mammoth bones that were apparently broken apart by deliberate force (?) or charred remains that suggest the puposeful use of fire, along with some stone flakes that might be tools (?). Some of the evidence seems maybe a bit more convincing, like obviously human footprints in a 23,000-year-old layer (because footprints can’t move from layer to layer).
But the difficulties with all of these examples are their isolation and lack of corroborating evidence. If bones were deliberately broken, where are the tools? If people were running around 23,000 years ago, where is all their stuff?
Most archaeologists would say that the most-solid evidence, considered together, leaves open the possibility of settlement here back to about 16,000 years ago, but it starts to get very sketchy before that. In addition to archaeological evidence, one of the main reasons is genetic, as this 2016 Science study indicates, for example (emphasis mine):
We sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons dating from 8.6 to 0.5 ka, allowing a detailed, temporally calibrated reconstruction of the peopling of the Americas in a Bayesian coalescent analysis. The data suggest that a small population entered the Americas via a coastal route around 16.0 ka (thousand years ago), following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations.
That brings us to the Nipéhe (Cooper's Ferry) site in Idaho, on the Salmon River, just off the Columbia River:
The Nipéhe (Cooper's Ferry) site in western Idaho. Now we’re talking — I agree wholeheartedly with the choice of this place to live. The hillllls are aliiiive…..
It just so happens that about 16,000 years ago, it would be an easy place to end up if you had gone around the Cordilleran ice sheet. You’d find the Columbia River, and before long, the Salmon River:
The Pacific Northwest about 16,000 years ago. SRMG: Salmon River mountain glaciers, GLM: Glacial Lake Missoula, GLC: Glacial Lake Columbia, MF: modeled extent of the Missoula Flood, tan dotted area: Pacific shoreline extent
The prehistoric people in that area would dig small pits, apparently to store things in, refill them with pebble gravel, and mark them on top with cairns. They seem to have continued to do this for a very long time. You can tell approximately when a pit was dug first of all by noting what layer it starts in, and then better yet, by dating the material you find in it. Here is what one of those pits looks like when you empty it of the gravelly material filling it:
One particular layer called LUB3 is now about 10 feet beneath the ground. It’s about 16 inches thick and is made up of loess (sediments exposed after periodic flooding and drying and then windblown). Loess is commonly found today at ground level in western Idaho and eastern Washington and in some areas forms some very cool wavy structures:
Hills northeast of Walla Walla, Washington, an area called the Palouse
Within that LUB3 layer, three pits were found, called F151, F78, and F108. They were dug starting from almost exactly the same level, and each is about 12-18 inches deep. Their radii are similar to their heights, and they’re very close to one another. All of this suggests they were dug around the same time.
A diagram of the pits and locations of artifacts found within and around them
When you sift through the pits, you often find animal bone fragments, sometimes charcoal, stone flakes such as left over from toolmaking (“debitage”), and — if you’re lucky — a few of these stemmed points. It seems that the pits were probably used to store things like hunting supplies, and presumably they were emptied and refilled frequently. I’m guessing that in their heyday you might have found a cache of points under the gravel in one, but we happen to have hit on a few here that had a small number of leftovers that didn’t get picked up at the last refill. Or maybe the rest of them were even better-looking than these, and the hunters picked through them and didn’t want to take along these leftovers.
Of course you can’t date the tips directly with carbon-14 dating because they don’t have any carbon in them! So you have to date the stuff around them that does, like the bone fragments. You might worry that stuff from different times could mix in and obscure the real dates, and that’s a legitimate worry, to be sure. But when several fragments from each pit were dated with the help of Oxford University (UK), they all gave the same answer: 15,955 to 15,625 calendar years before the present.
About a thousand years before there would be any chance to get through the ice-free corridor.
If these people did come by boat, and had settlements at the shore at first, it would be pretty tough to find any evidence of that, because sea levels have risen substantially since then, and all those sites would be well underwater now. (But people are trying anyway!)
I mentioned that these tips look similar to Northeast Asian ones that predate them by a bit, and just for completeness I have a diagram of what some of those excavated from the Japanese island of Hokkaido look like and their dates:
Upper row: ~21,400-19,830 calendar years before present; Lower row: ~16,750-16,170 calendar years before present
Certainly doesn’t prove anything, but looks very consistent with what we are finding and does permit the dates we are seeing.
So amidst the flurry of claims that sites have been found predating the ice-free corridor, we appear to have something pretty solid here, and it lines up with the other archaeological and genetic evidence, too. More and more evidence will be found, of course, hopefully some of it from submerged coastal sites, and that will keep on completing the story.
But the conclusion that’s hard to escape is that there is an extremely distinctive group of people living in Idaho. Their ancestors had already claimed an important place in recent American history for which we should be thankful:
Lewis and Clark met the Nez Perce in September of 1805. They saved the expedition from starvation and formed a bond of friendship.
Captains Meriwether Lewis and William Clark crossed Nez Perce country in the fall of 1805 and again in the spring of 1806. With the exception of their winter encampments, the Corps of Discovery spent more time among the Nez Perce than any other group they encountered in their journey. After some initial apprehension, the Nez Perce embraced the expedition, providing aid during a very trying time and remained friendly to Lewis and Clark when they returned in 1806.
But their more-distant ancestors can lay claim to the most foundational part of our history: they were the first humans to set foot here. The Nez Perce are very much alive and with us. We should recognize them for the American treasure they are, descendants of the first people ever to come here, looking for a better life.
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UPDATE (7:58 PM ET, 12/28): After much (well-deserved) badgering, I did change the title of the diary, with the realization that while it may have sounded appealing, it was an oversimplification in many ways. Thanks to those in the comments who pointed this out.
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