Beginning at the point where the seventh standard parallel intersects the main channel of the Missouri River; thence east along the seventh standard parallel to the southeast corner of township one hundred twenty-nine north, range seventy-four west of the fifth principal meridian; thence north along the line between ranges seventy-three and seventy-four west to the     northeast corner of township one hundred thirty-two north, range seventy-four west, a point on the eighth standard parallel; thence west along the eighth standard parallel to the southeast corner of township one hundred thirty-three north, range seventy-four west; thence continuing north along the line between ranges seventy-three and seventy-four west to the northeast corner of township one hundred thirty-six north, range seventy-four west, a point on the ninth standard parallel; thence west along the ninth standard parallel to the main channel of the Missouri River; thence in a southerly direction along the main channel of the Missouri River to the point of beginning.