English: The Wichita Mountains are located in the southwestern portion of the U.S. state of Oklahoma and represent the principal relief system in the Southern Oklahoma Aulacogen.The mountains are a northwest-southeast trending series of rocky promontories, many capped by 500 million-year old granite. These were exposed and rounded by weathering during the Pennsylvanian & Permian Periods.The mountains originally were considerably higher than the present ones as erosion has stripped off the upper parts and deposited the material in the intervening flats. This is a view of Mt. Sheridan (height, 2,385 feet; named after United States Army officer and Civil War Union General, Philip Henry Sheridan) from nearby, boulder-strewn Mt. Scott (height, 2,464 feet) in the Wichita Mountains Wildlife Refuge, the oldest managed wildlife facility in the United States Fish and Wildlfe Service system. Mt. Sheridan (top, right of center) consists of a layer of light colored granite overlying a layer of darker gabbro that dates to 530 to 520 million years ago. The tree line essentially marks the division between these two layers.