The badlands of South Dakota form a vast protected wilderness today. However, paleontological evidence shows that ancient Native Americans used the area as their hunting grounds, as did the tribes of the Sioux Nation in later years. The stratified layers of sedimentary rock show the changes over eons in the earth’s surface, which first emerged from under the sea as tropical land and then slowly changed to open woodland. Gray bands show evidence of volcanic eruptions at certain times in history. Geologists now have a good idea of what each layer represents, and there are many strata!