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:
This profile has the birth of one Mary Byram (only it's Bridgewater, Massachusetts, not Maine) and it has the death date of an entirely different Mary Byram. Take a look at the two profiles, and your records, and decide which one she is. Change the birth or death date and propose a merge.