The Teton Range, a north-south chain of mountains in the U.S. state of Wyoming, is noted for its Alpine scenery. The Tetons have craggy peaks and vertical cliffs. They rise straight up from the valley floor. How did the Teton Mountains get their unique form? Earthquakes, tectonic uplift and erosion. A series of earthquakes between 6 and 9 million years ago caused the earth's crust to stretch, thin and finally crack. The break in the earth's surface known as a fault forced the land to move. One block was pushed skyward and one block was pushed downward in the geological process known as tectonic uplift. Rivers of ice called glaciers fashioned the towering Tetons and low-lying valley in the last ice age. Advancing glaciers carved steep canyons and cut deep hollows. Retreating glaciers created the shallow lakes called kettles and step-like flats known as terraces. And they deposited huge piles of rock, gravel and boulders forming moraines.