Thank you so much for your quick response!
The family tree I created is on Ancestry and I previously had an Irish genealogist helping me try to break through my John Melvin "brick wall."
I have a Family Search ID number documenting his birth. But I don't know how to "search by ID" in that software. (I do have an account and have read the help info. So, I know all about the function of an ID. But none of the examples shows how to search by ID.)
From the Ireland, Catholic Parish Registers, 1655-1915, I do have John Melville's marriage record to Mary Money, which took place in Kiltullagh, Ireland on 30 April 1844. Also in Kiltullagh, documentation for birth of 2 Irish born children (all from Family Search.) Shortly thereafter they immigrated to America.