Help: Alexander & Mary Mx

Hi Folks;

As I'm entering data into my family tree software, I find that the wife of Henry Boehm Mx (son of the Rev. Amos N. Mx) is practically an unknown.

She's mentioned in Charles Green's letters, as is her father Alexander "Sandy". Myrtelle Wheeler Mx stated that Mary was Henry B. Mx's "second half-cousin, who descended from Levi and his first wife , whose name we are still seeking." Furthermore, the 1880 Census* for Henry, et al, also lists a female, probably Mary's sister, who according to Ancestry is named Jane, but looks more like Clara to me. Her surname is "Molynaux". These two factors lead me to suspect that Mary's surname (and by default, Alexander's) was some version of Mx. Can any of our readership shed some light on this issue?

(* Source Citation: Year: 1880; Census Place: Whiteplains, Westchester, NY; Roll: T9_945; Family History Film: 1254945; Sheet: 5A; Page: 350; ED: 101; Image: 0701.)

Thanks, Wayne