OOPS!!!
i just re-read your reply to me and saw James DID have a son named John b. about 1878 which, if correct, might make him too young to father my grandmother.

did john of 1878 or his father, james, emigrate to the u.s. and settle in brooklyn, n.y.?
did john of 1878 marry and to whom? (no one in the family knows my grandmother's mother's name)
did john of 1878 have a daughter named Mary born in brooklyn and a son named roswell also born in brooklyn?
roswell hated his name and was called ros (pr. roz) forever more.

thanks, kate