"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M6QP-RZW : accessed 24 September 2018), Mary A Layton in household of Howard Layton, Johnsons, Garrett, Maryland, United States; citing ED 111, sheet 5A, line 24, family 80, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 673; FHL microfilm 1,820,673.
It may be possible to confirm family relationships with Mary by comparing test results with other carriers of her 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:
McKenzie-3753 and Mckenzie-3447 appear to represent the same person because: Fathers name is with lower-case K. exact same father on both profiles, same spouse name on both profiles (in process of merge), same birth date and state, same death date and location