Beginning at a point in the middle of the main channel of the Missouri River, where a prolongation south of the range line between ranges six and seven, west, would intersect the same; thence north with said range line to the northeast corner of township forty-nine, range seven, west; thence west with the township line between townships forty-nine and fifty to the main fork of Cedar Creek; thence down said creek, in the middle of the main channel thereof, to its southern intersection with the range line between ranges eleven and twelve; thence south with said range line to the middle of the main channel of the Missouri River; thence down said river, in the middle of the main channel thereof, to the place of beginning.