The Teton Range is not symmetrical. The highest peaks lie near the eastern edge of the mountain block, rather than along its center, as is true in conventional mountains, and the western slopes are broad and gentle in contrast to the precipitous eastern slopes. The northern end of the range disappears under enormous lava flows that form the Yellowstone Volcanic Plateau. Even from this altitude the outlines of some of these flows can be seen. On the south the Teton Range abuts almost at right angles against a northwest-trending area of lower and less rugged mountains (the Snake River, Wyoming, and Hoback Ranges). These mountains appear altogether different from the Tetons. They consist of a series of long parallel ridges cut or separated by valleys and canyons. This pattern is characteristic of mountains composed of crumpled, steeply tilted rock layers—erosion wears away the softer layers, leaving the harder ones standing as ridges. On the east and northeast, Jackson Hole is bounded by the Gros Ventre and Washakie Ranges, which are composed chiefly of folded hard and soft sedimentary rocks. In contrast, between these mountains and the deepest part of Jackson Hole to the west, thick layers of soft nearly flat-lying sedimentary rocks have been sculptured by streams and ice into randomly oriented knife-edge ridges and rolling hills separated by broad valleys. The hills east of the park are called the Mount Leidy Highlands and those northeast are the Pinyon Peak Highlands. A pilot’s view If you descend from 100 miles to about 5 miles above the Teton region, the asymmetry of the range, the extraordinary variety of landscapes, and the vivid colors of rocks become more pronounced. Figure 2 shows a panorama of the Teton Range and Jackson Hole from a vantage point over the Pinyon Peak Highlands. The rough steep slopes and jagged ridges along the east front of the range contrast with smoother slopes and more rounded ridges on the western side. Nestled at the foot of the mountains and extending out onto the floor of Jackson Hole are tree-rimmed sparkling lakes of many sizes and shapes. Still others lie in steep-sided rocky amphitheaters near the mountain crests. One of the most colorful flight routes into Jackson Hole is from the east, along the north flank of the Gros Ventre Mountains. For 40 miles this mountain range is bounded by broad parallel stripes of bright-red, pink, purple, gray, and brown rocks. Some crop out as cliffs or ridges, and others are _badlands_ (bare unvegetated hills and valleys with steep slopes and abundant dry stream channels). In places the soft beds have broken loose and flowed down slopes like giant varicolored masses of taffy. These are mudflows and landslides. The colorful rocks are bounded on the south by gray and yellow tilted layers forming snowcapped peaks of the Gros Ventre Mountains.