"United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MHVJ-24Z : 4 April 2020), Mary Hurtz in household of Michael Hurtz, Monroe, Clark, Indiana, United States; citing family 207, NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).
"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MHMJ-ZHC : 7 September 2017), Mary Hartz in household of Michael Hartz, Oregon, Clark, Indiana, United States; citing enumeration district ED 32, sheet 220B, NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm 1,254,269.
Find a Grave, database and images (accessed 18 June 2020), memorial page for Mary Hartz (6 Mar 1814–12 Sep 1881), Find A Grave: Memorial #97482692, citing Walnut Hill Cemetery, Marysville, Clark County, Indiana, USA ; Maintained by Cyndi (contributor 46928998) .