Out of some sixty aboriginal stocks or families found in North America above the Tropic of Cancer, about five-sixths were confined to the tenth of the territory bordering Pacific ocean; the remaining nine-tenths of the land was occupied by a few strong stocks, comprising the Algonquian, Athapascan, Iroquoian, Shoshonean, Siouan, and others of more limited extent.
The Indians of the Siouan stock occupied the central portion of the continent. They were preeminently plains Indians, ranging from Lake Michigan to the Rocky mountains, and from the Arkansas to the Saskatchewan, while an outlying body stretched to the shores of the Atlantic.