This is a fossil of an earthquake. It is a place where the forces on our plates caused one to split apart and move, creating a M 7.5 temblor beside Hebgen Lake near Yellowstone National Park. The 1959 earthquake did almost $11 million in damage (about $90 million in 2015 money); worse, it triggered a landslide and killed 28 people. Today, about all that remains is this fault scarp.
The amazing thing about the scarp is that it shows how many mountains form, one earthquake at a time. Each temblor creates a small uplift. And hundreds of thousands of these small uplifts end up in mountains like the Rockies and Appalachians.