|About 600,000 years ago, huge volcanic eruptions occurred in Yellowstone, emptying a large underground magma chamber. Volcanic debris spread for thousands of square miles in a matter of minutes. The roof of this chamber collapsed, forming a giant smoldering pit. This caldera was 30 miles (45 km) across, 45 miles (75 km) long, and several thousand feet deep. Eventually the caldera was filled with lava.
One of these lava flows was the Canyon Rhyolite flow, approximately 590,000 years ago which came from the east and ended just west of the present canyon. A thermal basin developed in this lava flow, altering and weakening the rhyolite lava by action of the hot steam and gases. Steam rises from vents in the canyon today and the multi-hued rocks of the canyon walls are also evidence of hydrothermally altered rhyolite.
Other lava flows blocked rivers and streams forming lakes that overflowed and cut through the various hard and soft rhyolites, creating the canyon. Later the canyon was blocked three different times by glaciers. Each time these glaciers formed lakes, which filled with sand and gravel. Floods from the melting glaciers at the end of each glacial period recarved the canyon, deepened it, and removed most of the sand and gravel.
The present appearance of the canyon dates from about 10,000 years ago when the last glaciers melted. Since that time, erosional forces (water, wind, earthquakes, and other natural forces) have continued to sculpt the canyon.
Inspiration Point Platform
A member of the Washburn party in 1870, Nathanial P. Langford, used these words to describe his visit to this point:
"The place where I obtained the best and most terrible view of the canyon was a narrow projecting point situated two to three miles below the lower fall. Standing there or rather lying there for greater safety, I thought how utterly impossible it would be to describe to another the sensations inspired by such a presence. As I took in the scene, I realized my own littleness, my helplessness, my dread exposure to destruction, my inability to cope with or even comprehend the mighty architecture of nature."
Red Rock Point
Brink of the Lower Falls
Over the years the estimates of the height of this falls has varied dramatically. In 1851 Jim Bridger estimated its height at 250 feet. One outrageous newspaper story from 1867 placed its height at "thousands of feet". A map from 1869 gives the falls its current name of Lower Falls for the first time and estimates the height at 350 feet.
It mattered little how tall the observers thought the falls was. They consistently write journal entries that comment on its awe-inspiring nature. A member of the 1870 Washburn party N. P. Langford gave this brief but poetic description: "A grander scene than the lower cataract of the Yellowstone was never witnessed by mortal eyes."
The Brink of the Upper Falls
This falls was called the "upper falls" for the first time by members of the 1869 Folsom party who estimated its height at 115 feet. Visitors to the Brink of the Upper Falls have throughout time found the power of the experience worthy of detailed description.
In 1870 N.P. Langford of the Washburn party wrote of his visit to the brink:
"Mr. Hedges and I made our way down to this table rock, where we sat for a long time. As from this spot we looked up at the descending waters, we insensibly felt that the slightest protrusion in them would hurl us backwards into the gulf below. A thousand arrows of foam, apparently aimed at us, leaped from the verge, and passed rapidly down the sheet. But as the view grew upon us, and we comprehended the power, majesty and beauty of the scene, we became insensible to the danger and gave ourselves up to the full enjoyment of it."
Upper Falls Viewpoint
According to a companion, the famous mountain man Jim Bridger visited this waterfall in 1846. Word spread of its existence and in the 1860s some prospectors went out of their way to visit it.
View of the Lower Falls from Uncle Tom’s Trail
Today Uncle Tom’s Trail is very different from the simple trail used by Mr. Richardson and his visitors. It is still, however, a very strenuous walk into the canyon. The trail drops 500 feet (150 m) in a series of more than 300 stairs and paved inclines.
The name Artist Point is believed to have been given to this location around 1883 by Park Photographer F. Jay Haynes. The name appeared in print for the first time in Mr. Haynes guidebook, published in 1890.
Silver Cord Cascade
Members of the Washburn party discovered the cascade in 1870 and named it Silverthread Fall. In 1885 the USGS Hague parties gave it the name that survives today, Silver Cord Cascade.
Information provided by the National Park Service