Historical Marker
Art Gallery of Time
Sweetwater County · Wyoming
Only the first of the two voyages the panel describes went through the Grand Canyon. The 1869 party reached the mouth of the Virgin River on August 30. The second, which launched from Green River in 1871, ended its work with the boats at Kanab Canyon in 1872 and carried on its mapping and photography on land north of the canyon. Its artist, Frederick Dellenbaugh, complained that Powell's report on the river gave the second party no credit and that no record of its trip was ever published, and he set one down himself in A Canyon Voyage.
What the plaque says
Art Gallery of Time Major John Wesley Powell named the Flaming Gorge and tributaries such as Little Firehole Canyon for the brilliant red sandstones exposed in the canyon walls. Embarking from what is now Green River, Wyoming in specially designed river dory boats, Powell completed two voyages down the Green and Colorado rivers through the Grand Canyon. The first, in 1869, was largely exploratory. The second, in 1871, collected scientific data and produced the first maps of the upper Colorado drainage system. Powell's work formed the basis for much of what geologists now know about the region. The Green River through Flaming Gorge is a classic example of a superposed stream - it flows across the eastern end of the Uinta Mountains, rather than draining away from the mountains. Geologists believe that, when the last major regional erosion cycle began several million years ago, an extensive landscape nearly level with the present crest of the Uintas dominated southern Wyoming. As erosion removed softer rock, the river level was gradually lowered, cutting a precipitous canyon into the resistant core of the Uintas. The result is the spectacular Red Canyon of the Green River, which chronicles earth history. Rocks in the very near area are young, only about 49 million years old. Traveling down tributary canyons, such as Little Firehole, and continuing downstream towards Flaming Gorge Dam, older rock formations contain a wide variety of fossils, ranging from dinosaurs to primitive sea life. Near Flaming Gorge Dam, the dark red sandstones and shales of the pre-Cambrian Uinta core form the near vertical canyon walls. These rocks are nearly 1.1 billion years old.
Where it stands
41.40434, -109.30733 · Directions
Worth the stop nearby
- Expedition Island — 12 miWhere John Wesley Powell's 1871 survey left for the canyons of the Green and Colorado; where his 1869 trip started has never been proven.