forces had uplifted a broad part of western Wyoming into a continuous high plateau. This region includes areas now occupied by the Teton Range, Gros Ventre Range, Wind River Mountains and other mountain ranges to the south and east of the Tetons. A separate area of uplift called the Targhee Uplift formed north of park borders around this time. Subsequent erosion of the Targhee Uplift was driven by steepened stream gradients. Gravel, quartzite cobbles, and sand from this erosion eventually became the 5,000 foot (1,500 m) thick Harebell Formation seen today as various conglomerates and sandstones in the northern and northeastern parts of the park. In the Paleocene epoch large amounts of clastic sediment derived from uplifted areas covered the Harebell Formation to become the Pinyon Conglomerate. The lower members of this formation consist of coal beds and claystone with conglomerate made of quartzite from the Targhee uplift above. The subducting Farallon Plate was eventually completely consumed below the North American Plate, bringing an end to the Laramide orogeny. Hot and semi-plastic rock deep below western North America responded to the lack of compression beginning 30 million years ago by slowly rising; gradually pushing the overlying rock sideways both east and west. Blocks of the brittle upper crust responded by breaking along roughly parallel north-to-south trending normal faults that each have a subsiding basin on one side and a mountain range on the other. This stretching may have begun to tear apart the previously-mentioned high plateau in western Wyoming around this time, but evidence from ancient sediments indicates that the Teton Fault system developed much later (see below). An eastward-moving intensification of this process began 17 million years ago, creating the Basin and Range geologic province in Nevada and western Utah. Stretching of the crust in this region eventually exceeded 200 miles (320 km), doubling the distance between Reno, Nevada, and Salt Lake City, Utah. Waning of the Laramide orogeny coincided with volcanic eruptions from two parallel volcanic chains separated by a long valley in the Yellowstone-Absaroka area to the north. Huge volumes of volcanic material such as tuff and ash accumulated to great depth in the Grand Teton area, forming the Absaroka Volcanic Supergroup. Additional eruptions east of Jackson Hole deposited their own debris in the Oligocene and Miocene epochs. Sediment collected in various lakes in the area from around 17 to 15 million years ago, becoming the Miocene-aged