Iowa Code § 556F.5: Advertisement — when title vests.

In all cases where any vessel, watercraft, logs, or lumber shall be taken up as aforesaid, which shall be of a value less than five dollars, the finder shall advertise the same by posting a notice of such finding in three of the most public places in the neighborhood; but in such cases the finder shall keep and preserve the same in the finder’s possession, and shall make restitution thereof to the owner, without fee or reward, except the same be given voluntarily when the owner claims the same, provided it shall be done in three months from such taking up or finding; but, if no owner shall claim such property within the time aforesaid, the exclusive right to it shall be vested in the finder.