Beginning at a point in the middle of the main channel of the Mississippi River, where the prolongation east of the line dividing townships fifty-six and fifty-seven would intersect the same; thence west with said line to the northeast corner of section six, township fifty-six, range seven; thence south with the subdivisional line to the southeast corner of section seven, township and range aforesaid; thence west with the subdivisional line to the southwest corner of section seven, township fifty-six, range eight, west; thence north with the range line between ranges eight and nine to the northwest corner of township fifty-nine, range eight; thence east with the township line between townships fifty-nine and sixty to its termination; thence with said line, where it prolongs east, to the middle of the main channel of the Mississippi River; thence down the Mississippi, in the middle of the main channel thereof, to the place of beginning.