Iowa Code § 589.10
If an assignment of a mortgage or other recorded lien on real estate has been executed more than ten years earlier, by written assignment on the margin of the record where the mortgage or other lien is recorded or entered, the assignment passed all the right, title, and interest in the real estate, which the assignor at the time had, with like force and effect as if the assignment had been made by separate instrument duly acknowledged and recorded; and an assignment or a duly authenticated copy of an assignment when accompanied by a duly authenticated copy of the record of the instrument or lien it purports to assign, is admissible in evidence as provided by law for the admission of the records of deeds and mortgages.
Iowa Code § 589.10
84 Acts, ch 1090, §9; 91 Acts, ch 183, §19