Mary Martin, wife of Nicholas Martin, was born in August of 1751. She married Nicholas Martin in Montgomery County, Pennsylvania, although no marriage record remains. We know that this is where they married because husband Nicholas never left the county; he was born there and died there.
All that we have that even shows the existence of Mary Martin is her tombstone, in Worcester Township, and her children. Records for Mary's baptism do not seem to exist; we have her precise birth date, and nothing on-line matches. There is a possibility of a match if one presumes that Mary was actually born a month later than stated -- but if so, she'd be a Sommer, and she would have definitely died in Virginia, not Pennsylvania.
Baptism records do not seem to have been preserved for any of her children either. But one of her children, Sarah R Martin, never married, and carries an interesting middle initial. It is my theory that her middle name is, in fact, the maiden name of her mother, as was often done in that era.
As for what "R" stands for, it would have to be a family surname beginning with "R" that was common in the Montgomery County area. This, of course, doesn't help much, but we can perhaps get a hint based on who Nicholas Martin's siblings married. Here, there are no "R" surnames, but not just one but TWO siblings married into the Troxell family. And the Troxell family married into the Reitenauer clan.
The Reitenauers were Huguenots who immigrated to Maryland via Philadelphia, but they left behind a brother (Hans "Hannes" Balthasar Reitenauer) and all of his children. Baptism records for Hannes's grandchildren abound. Mary's, of course, is not among them -- but there are a number of Reitenauer families she could have come from -- if she's indeed a Reitenauer. I've tucked her into one such family for the time being.
The object of this discussion is to: (a) try to confirm that Mary is really a Reitenauer, and (b) if so, figure out which son's family she probably came from.