There are some sections of our extensive country almost as little known as the interior of Africa. The St. Louis (Mo.) Republican states that a party has just recently returned to that city from an exploring expedition in a wild region known by the above appellation. It is a vast country of movable sands, sterile, bleak and inhospitable. There are small streams at remote distances in it, upon which there is spare vegetation ; sufficient, however, for the subsistence of the Indians' horses and some buffalo. It must ever be the home of nomadic tribes, who wander about like those of the wild wastes of Asia in search of the small patches of pasturage which are fructified by the irrigation of distant rivulets. This country has been supposed to be fertile from its geographical position and its appearance upon the map, but it proves to be wholly otherwise. The party consisted of sixty men, and the Sioux, who are numerous there, forbid the return of any more white men. They said that this party might pass, because it was the first, but no others must come, as they scared away their game, and would discover their strongholds and hiding-places.