↑1850 United States Federal Census, database and images, Ancestry, 2009 (http://www.ancestry.com : accessed 26 April 2017), digital image, Mary E Clark, Taylor, Greene, Indiana; citing Roll: M432_148, Page: 413B, Image: 275, Seventh Census of the United States, 1850, Records of the Bureau of the Census, National Archives, Washington, D.C.
↑ 2.02.1 "Public Family Tree", database, RootsWeb (http://wc.rootsweb.ancestry.com : accessed 6 March 2015), Bell County, Kentucky Families, database by Sueann Morrow, entry for ID I086507, Mary E. Clark (b. 1843, Ohio); undocumented data updated 17 July 2005.
It may be possible to confirm family relationships with Mary by comparing test results with other carriers of her ancestors' mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Mary: