When the cowboys and homesteaders arrived on the G reat Plains, Amerindian peoples like the Sioux had been roaming across them for hundreds o f years . The Sioux lived by hunting the buffalo. In the early part o f the nineteenth century an estimated twelve million of these gentle, h eavy animals wandered the Great P lains . They moved about in herds. Sometimes these herds were so big that they stretched as far as the eye could see. The buffalo pro v ided the Sioux with everything that they needed -food, clothing, tools, homes . In the 1840s wagon trains heading for Oregon and California began to cross the Great Plains. The Amerindians usually let them pass without trouble. Then railroads began to push across the grasslands. The railroads carried white people who stayed on the prairies and began to plough them. At first the Amerindians tried to drive the newcomers away from their hunting grounds. But soon they saw that this was impossible. So th...