Little is known of the prehistory of the region which comprises Badlands National Monument. The time of man’s entry into the Badlands-Black Hills region is unknown. The oldest Indian site found in western South Dakota is in the Angostura Basin south of Hot Springs. Studies indicate it to be a little more than 7,000 years old. Evidence shows that these early people were big-game hunters who preyed upon mammoth, large bison, and other animals that lived in the lush post-glacial grasslands.[1] Firepits containing Indian artifacts have been found in the Pinnacles area of the national monument. Radiocarbon studies leave little doubt that hunters were already using this site by 900 A.D.[2] More archeological research will probably show that man hunted and made his home in the Badlands long before that date.[3] Since about 1000 AD. the Black Hills area has been occupied by a number of nomadic Indian tribes. Some of these subsisted primarily by hunting, while others lived on local food plants. These tribes probably belonged to the Caddoan, Athabascan, Kiowa, and Shoshonean linguistic groups.[4] During the 18th century, parties of Arikara from the Missouri River went on buffalo hunts as far west as the Black Hills. There they met with the Comanche, Arapaho, Kiowa, and Cheyenne at trading fairs where they acquired horses. The Arikara, in turn, traded horses with the Teton Sioux who had been slowly migrating south and westward since about 1670 from the headwaters of the Mississippi River. Around 1775 the Oglala and Brule, tribes of the Teton Sioux, moved west of the Missouri River to occupy respectively the Bad River country (around the present town of Philip, S.D.) and the region along the White River south of the Badlands. Because of their move from a timbered area to a plains region, the Sioux underwent great adjustment. As the result of acquiring guns from the whites and horses from other tribes, the Sioux became primarily a nomadic people, dependent on buffalo for sustenance.[5] For more than a century prior to 1763, the upper Missouri Valley, including what is today Badlands National Monument, was under French control. Under terms of the Treaty of Paris of 1763 French possessions west of the Mississippi River were ceded to Spain. Spain returned the area, known as Louisiana, to France in 1800 in the secret Treaty of San Ildefonso.[6] In 1803 the entire region, which included all of the present states of Arkansas, Missouri, Iowa, Nebraska, and South Dakota, plus parts of eight other states, was purchased by the United States from France for $15,000,000.