• The Cathedral Group from the Teton Park Road

    Grand Teton

    National Park Wyoming

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  • Seasonal road closures in effect

    Seasonal road closures are in effect for motorized vehicles. The Teton Park Road is closed from the Taggart Lake Trailhead to the Signal Mountain Lodge. The Moose-Wilson Road is closed from the Granite Canyon Trailhead to the Death Canyon Road. More »

  • Avalanche hazards exist in the park

    Avalanche hazards exist in the park, especially in mountain canyons and on exposed slopes. A daily avalanche forecast can be found at www.jhavalanche.org or by calling (307) 733-2664. More »

  • Bears emerging from hibernation

    Bears are beginning to emerge from hibernation. Travel in groups of three of more, make noise and carry bear spray. Visitors must stay at least 100 yards from bears. More »


The Teton Range does not conjure visions of vast, ancient seas; the peaks seem too powerful and imposing. The landscape of Grand Teton National Park, however, reflects both scenes. Sedimentary rocks deposited by ancient seas drape over crystalline bedrock found in the high peaks. Fossils are the mineralized remains or impressions of plants or animals from the geologic past, and provide geologists with clues to unravel the history of the area.

Fossils occur in sedimentary rock. Material such as gravel, sand, or mud settles from water into horizontal layers. With time, these layers become buried, compressed, and lithify (harden to rock). Organic material such as plant and animal remains settles along with the sediment, buried within the layers. As the waters recede, sedimentary rocks are exposed to erosive forces such as wind, rain, ice and gravity. These forces break down the rocks exposing each successive underlying layer. Eventually, the fossil remains of a creature once buried under thousands of feet of sedimentary rock may be exposed at the Earth's surface.

Grand Teton National Park has exposures of sedimentary rocks over a thousand feet thick in the northern, southern, and, most dramatically, in the western portions of the park. Many of these formations contain the fossil remains of marine organisms. The presence of these fossils indicate that where the Teton Range now stands was once the floor of an ancient sea inhabited by algae, coral, brachiopods (clam-like shells), and trilobites.

Fossils do more than provide us with a fascinating look at prehistoric life forms. They are useful tools to date geologic features, analyze past climates and trace evolutionary processes. If you are fortunate enough to find a fossil during a visit to a national park, please look but do not take. Leave the fossils to be rediscovered by other visitors and scientists in the future.

Did You Know?

Uinta Ground Squirrel

Did you know that Uinta ground squirrels, sometimes mistaken for prairie dogs, hibernate up to eight months a year? These animals leave their burrows in March or April to inhabit the sagebrush flats, but may return by the end of July.