I'm stretching a bit but bear with me;

In the land patent records for Cedar County there are two entries for a John H Garrison in 1857., William Hamlett ends up with one of the neighboring plots in 1872. Thus maybe Henry Garrison is really John Henry Garrison? See

http://www.glorecords.blm.gov/details/patent/default.aspx?accession=MO5550__.149&docClass=STA&sid=cap5lqkn.x2r#patentDetailsTabIndex=2

John R