Upon the completion of the exchange authorized by there shall be, and is, relinquished and quit-claimed to said owner any right, title, and interest that the United States of America may have in and to the now existing road over other land of said owner in the Grand Canyon National Park, the center line of said road being described as follows: Beginning at a point approximately at the south quarter section corner of section 17, township 30 north, range 4 east, Gila and Salt River meridian, Arizona, thence north ten degrees eleven minutes west, five hundred feet; thence north thirty-six degrees six minutes west, one hundred and forty-five feet; thence north forty-two degrees sixteen minutes west, one thousand seven hundred feet to the east line of the west half of the west half of said section 17.section 221c of this title