Iowa Code § 622.47: Maps in office of surveyor general.

Copies of all maps, official letters, and other documents in the office of the surveyor general of the United States, when certified by that officer according to law, shall be received by the courts of this state as presumptive evidence of the existence and contents of the originals, and that they are copies of the originals, notwithstanding such maps, official letters, or other papers, may themselves be copied.