The main range of the Rocky Mountains separates that part which is drained west into the'Columbia river and the Pacific Ocean from that which is drained east into the Missouri and Mississippi rivers and the Gulf of Mexico, and from a very small part which is drained north-east into Hudson Bay; the water-parting which in Montana separates the drainage into Hudson Bay from the drainage into the Gulf of Mexico crosses only the north-west region of Teton county.
The finest examples of this kind are the moraines about Jackson Lake on the basin floor east of the Teton Range (Grand Teton, 13,747 ft.), a superb north-south range which lies close to the meridional boundary line between Wyoming and Idaho.
Included in the Dakota branch were the Santee and Teton tribes, the latter comprising the Brule, Blackfeet and Oglala Indians; in the Thegiha branch were the Omaha and Ponca tribes; and in the Chiwere branch, the Iowa, Oto and the Missouri tribes.
