Visit to Fort Rock in the Oregon desert is a trip back in time — way back

With hoopla coming up this year about the 250th anniversary of the founding of the United States, it’s a good time to consider that people founded settlements in Oregon 18,000 years earlier.

University of Oregon researchers keep pushing back the clock about the human settlement of America, first with Luther Cressman’s discovery of 9,000-year-old sandals in a cave at Fort Rock, then with Dennis Jenkins’ proof of 14,300-year-old human DNA at Paisley Cave, and now with Patrick O’Grady’s revelation that people killed and ate camels 18,300 years ago in Rimrock Draw near present-day Burns.

I’m a fifth-generation Oregonian, which admittedly doesn’t seem like much in the scale of things. Because I write hiking guidebooks for a living, I’m going to suggest you take a walk in the desert to see the most visitable of these caves for yourself. Maybe not in January, when icy winds rake the sagebrush, but certainly in early spring, when the desert blooms and you want to escape the rain of western Oregon for a weekend.

Why has the best evidence of early people been found in eastern Oregon? The climate there is dry, preserving things well. But it’s also true that the western part of our state has not always been a friendly place to live.

For the first 6,000 years of human habitation, gigantic Ice Age floods roared down the Columbia River every 80 years or so, launched by a Canadian glacier that pinched off a branch of the Columbia River in present-day Idaho. Those floods killed everyone along the river and backed up 400 feet deep into the Willamette Valley. To this day, the Kalapuya tribe honors three sacred peaks that stood above the waters – Spirit Mountain near Grande Ronde, Mount Angel, and Marys Peak.

Excavations are likewise recent along the Oregon Coast. During the Ice Age so much water was converted to glacial ice that the coastline was 20 miles west of its current position. Coastal settlements from that era are now under 400 feet of water.

The Ice Age brought rain instead of ice to eastern Oregon. Southeast of Bend, the Fort Rock Valley filled with Oregon’s largest lake ever, inundating 1,500 square miles as deep as 250 feet. Plovers, ducks, and geese flocked to its reedy shore. Buffalo, elk, and deer roamed the grassy savannas along its banks. It was a great place for people to live.

Today, as you drive through a sea of sagebrush toward Fort Rock State Natural Area, it’s hard at first to visualize the immense lake that once lapped this desert rock’s walls. It’s easier to picture the lake after you’ve left the car and followed a park trail a few hundred yards up to the ancient beach. There, ringing the base of the rock’s orange, pockmarked cliff, is a rounded, ten-foot notch carved by the vanished surf.

If you want to visit Fort Rock, drive 25 miles south of Bend on Highway 97, turn left at a “Silver Lake” pointer on Highway 31 for 29.2 miles, and turn left at a “Fort Rock” sign for 6.5 miles. Turn left again just beyond the Fort Rock store, following signs 1.7 miles to Fort Rock State Natural Area. The route is entirely paved. Park at the far end of the picnic area’s lot.

Start by hiking counterclockwise around the inside of Fort Rock, contouring from one horn of the crescent to the other. Spring wildflowers make the desert bloom, and the huge blue sweep of sky is as intoxicating as the bittersweet smell of sagebrush.

But where is Fort Rock Cave, the sandal site? The cave isn’t on Fort Rock itself, but you can see it from there. Turn right at a four-way junction near the far side of Fort Rock’s crescent and climb to a gap high atop the rim wall. Look for the cave’s dark spot at the base of a small knoll more than a mile away, across a flat expanse of private ranchland. Waves from the Ice Age lake once rolled across this gulf and smashed into the knoll, carving the cave’s fifty-foot-deep overhang by washing soft earth from beneath a hard lava layer.

The first scientist to investigate the cave was Cressman, who had won secondhand fame for his brief marriage to the flamboyant South Sea island anthropologist Margaret Mead. Following their separation in 1928, Cressman began exploring eastern Oregon with a Model A Ford, a notebook and a revolver, intent on building a scientific reputation of his own. Hearing that pot hunters had scavenged artifacts from this cave, he undertook a methodical excavation, marking the cave floor into square meters and sifting the sand with a quarter-inch screen.

To Cressman’s disappointment, the earlier souvenir diggers left the top layer jumbled, destroying 3,000 years of archaeological record. But below that, and particularly beneath a multi-ton boulder that fell from the cave roof in an ancient earthquake, the intact strata began revealing astonishing finds: campfire wood from pinyon pine trees that no longer grow in Oregon, fishing net sinkers from a lake that no longer exists, and bones from an extinct species of buffalo.

Even more surprising, the richest finds lay below a thick layer of yellow volcanic ash. Could this be Mount Mazama ash, blasted here when Crater Lake’s volcano exploded 7,700 years ago? In 1938, there was no dating system that could prove Cressman’s guess, but his theory shook the archaeological world. Most experts believed the first Indians arrived here only 1,000 years ago.

In 2008, Jenkins, a UO archaeologist, revealed that 14,300-year-old human DNA had been found in coprolites (dried feces) at the Paisley Caves, 50 miles southeast of Fort Rock. The discovery not only pushed back proof of human arrival in the Americas by additional thousands of years, but genetic analysis revealed the people here were descendants of Siberians, lending credence to the Alaska land bridge theory.

Since 2009, another UO archaeological team, led by O’Grady, has been finding even earlier evidence of humans at Rimrock Draw, 90 miles east of Fort Rock near the town of Riley.

Under the shelter of a rock ledge, O’Grady’s team found rock scrapers with the blood of now-extinct bison below a layer of 15,000-year-old Mount St. Helens ash. Even deeper were the teeth of now-extinct camels, also evidently hunted for food. In 2023, radiocarbon dating showed the teeth are 18,250 years old. And 10 centimeters below the camel teeth were more rock scrapers, used to clean camel hides.

The camels didn’t kill themselves.  Some of the earliest evidence of humans in the Americas is in Oregon, and it helps explain why most of the continent’s megafauna are extinct. The first people here found the big animals were easy to hunt, and ate them.

Credit for these discoveries goes partly to college kids.

Cressman founded the University of Oregon Field School in 1937, enlisting students to help at digs. In 1938, they helped unearth the Fort Rock sandals. In recent summers, they’ve been working at Rimrock Draw, sifting 10,000 bags of sand to winnow out the camel’s teeth and obsidian chips that drive science.

In a time when people think of themselves as Oregonians after a few months, and when celebrations tout a few centuries of colonialism, it’s sobering to hike in the Oregon desert, following the tracks of those who went before.