- Lon Austin
- Central Oregonian - News
Painted Hills unit of John Day Fossil Beds offers hikes, fossils and scenery
Except for the sparse vegetation and some lingering snow on the distant mountains, the scene reminded me of the colorful Martian landscape as viewed from one of the Mars Exploration Rovers. Layers of reds, oranges and blacks mixed within the greenish-gray hills seemed out of place in this otherwise neutral-colored juniper countryside.
If you like geology (rocks), paleontology (fossils), photography (taking pictures), footslogging (hiking) or just having some mirth (fun), then there's something for everyone at the Painted Hills.
Located about 50 miles northeast of Prineville, the Painted Hills (one of the three units of the John Day Fossil Beds National Monument) is just a few miles off of Highway 26 before reaching Mitchell. Look for the sign as you cross Bridge Creek.
My wife and I arrived at the Painted Hills late afternoon when lighting is best for viewing and photos. The first of our four hikes began with the Carroll Rim Trail, a 1 1/2 mile hike that climbs a few hundred feet from the overlook parking lot. Yellow bells and other small wildflowers could be seen popping up along the trail. Rock wrens sang from the rim and talus slopes.
Once on the ridge, there are great panoramic birds-eye views of the Painted Hills, Sutton Mountain and the volcanic country of the John Day River area. There's a bench at the end of the trail as well as pamphlets that provide information of the surrounding landscape. While sitting, reading and taking in the view, several butterflies flew by-a sure sign that spring has arrived.
The colorful claystones and clays of the Painted Hills owe their existence to volcanic eruptions that occurred about 33 million years ago when annual precipitation for the area was between 30 and 50 inches, compared with today's average of about 12 inches per year. Volcanoes from the ancestral Cascades deposited many layers of ash, which eventually became soil. Later deposits, followed by compaction, cementation and recrystallization, resulted in the colorful display.
The cap rock on Carroll Rim is called ignimbrite, which was deposited from a huge eruption about 29 million years ago. In the last few years, state geologists have discovered the largest volcano in Oregon, which they named the Crooked River Caldera. This 22-mile diameter mega-volcano is centered around Prineville and was responsible for many of the fossils in the monument today.
A fiery ash cloud of rocks, particles and gases swept over the land for over 100 miles like a tidal wave and finally hardened into a welded tuff. Subsequent faulting and other natural processes have since tilted the layers. Sutton Mountain to the east is capped with many layers of flood basalts. About 16 million years ago, lava flowed from dozens of events.
The trails on the Painted Hills are from deer and antelope. No hiking is allowed on any of the exposed hills in the monument. Fossil and rock collecting is prohibited.
Our next stop was the Leaf Hill Trail, a quarter-mile hike around a small hill where important scientific studies were made in the 1920s and 1930s. Thousands of leaf fossils found here give us a glimpse into the ancient past. Around 30 million years ago, the area held lakes and swamps that were surrounded by forests of dawn redwood, alder, oak, sycamore, beech, elm and maple. A few fossils are on exhibit at the trailhead.
Ralph W. Chaney, a University of California paleobotanist, collected fossils at the site in the 1920s. "I quarried 98 cubic feet of leaf-bearing shale from three pits in the low hill to the right of the road; I split the slabs of ashy shale into thin layers which yielded a total of 20,611 specimens," he wrote.
A 1993 study revealed evidence of a series of prehistoric ecosystems. Starting at the foot of the hill going up, there are deposits from an oak-sycamore forest, then savannah-like woodlands, two swamps then a succession of three lakes. Finally a hardwood forest, which was incinerated and inundated by hot ash fall during a volcanic eruption. A total of 35 species of plants were found here, most of which are no longer exist in the Pacific Northwest.
The diversity of fossils in the monument is tremendous - more than 2,200 species of plants and animals have been identified. There are close to 40,000 individual specimens at the visitor center in the Sheep Rock Unit near Dayville. In the entire National Park Service, there are only about a dozen paleontologists; three of them are stationed at the Fossil Beds.
Our next stop was the quarter-mile long Painted Cove Trail. The trail encircles a small red and gold claystone hill. Visitors get a close-up view of the popcorn-textured clay for which the unit is noted. The bentonite clay expands greatly when it absorbs water. The "popcorn-like" appearance occurs when the drying clay contracts, cracks and breaks apart. These clay particles are very sticky and absorbent and are often used as emulsifiers in toothpaste and chocolate, and in kitty litter.
The best place to end the day is at the Painted Hills Overlook. A half-mile trail heads up the ridgeline from the overlook, providing glimpses of the colorful Painted Hills from several angles. Benches are along the trail for those wishing to sit and take in the sun setting on the hills.
Although the layers of red, pink, bronze and tan first attract the eye, my favorite part of the Painted Hills is the black lines interspersed within the layers. The scene resembles an artist's canvas. Just before finishing the painting, the artist made his final strokes of the brush, bringing the black layers down to mix in with the other colors.
According to John Fiedor, park ranger and chief of visitor services at the monument, the entire monument averages about 120,000 visitors a year, with about five percent being international visitors. "People come not only for the fossils but also for the beautiful landscapes," Fiedor said.
As we walked up the trail with the sun dropping below the horizon and a western meadowlark singing from the nearby sagebrush, I realized there was no doubting the beauty of the area.