All deeds, mortgages, or other instruments in writing for the conveyance of lands which have been made and executed more than ten years earlier, and the officer taking the acknowledgment has not affixed the officer's seal to the acknowledgment; the acknowledgment is, nevertheless, good and valid in law and equity, any other provision of law to the contrary notwithstanding.
Iowa Code § 589.1
84 Acts, ch 1090, §1; 91 Acts, ch 183, §11