Devil's Slide is an unusual cliff rock formation on the side of Cinnabar Mountain located in Gallatin National Forest

Gallatin National Forest

Founded in 1899, Gallatin National Forest is located in south central Montana, United States. The forest comprises 2.1 million acres and has portions of both the Absaroka-Beartooth and Lee Metcalf Wilderness areas within its boundaries...

 in Park County, Montana

Park County, Montana

Park Counties in Montana and Wyoming are among the very few pairs of counties in the United States with the same name to border each other across state lines.-National protected areas:* Custer National Forest * Gallatin National Forest...

 north of Yellowstone National Park

Yellowstone National Park

Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...

. This distinctive formation can be viewed from Highway 89 and was created from alternate beds of limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

, sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

, quartzites  that have been tilted to lie nearly vertical and have eroded at different rates.

History

In 1871, very few white travellers had ventured this far south in the Yellowstone River

Yellowstone River

The Yellowstone River is a tributary of the Missouri River, approximately long, in the western United States. Considered the principal tributary of the upper Missouri, the river and its tributaries drain a wide area stretching from the Rocky Mountains in the vicinity of the Yellowstone National...

 valley. The Cook–Folsom–Peterson Expedition passed the Devil's Slide in 1870. Cook and Folsom described the slide in their diaries but did not name them

In August 1871, the Washburn–Langford–Doane Expedition observed the formation and named it The Devil's Slide. Langford described the formation in his Wonders of the Yellowstone published in 1871: