Thank you for returning my post.
I actually didn't have a 'Mary' as a child of Alexander and Margaret. The children I have for Alexander and Margaret are:
William, Jane, Ann, Helen, John, Simon, Alexander, David, George and John (John married Helen Sutherland-my Grandmother's Mother in 1871).
I have very little information on Helen Sutherland, other than her parents are William Sutherland and Margaret Flett.
I would appreciate whatever information you can provide.
You are welcome to contact me at my email firstname.lastname@example.org