Ms Goldfield, with respect, I beg to inform you of a few facts.
First: to the best of my knowledge no one has yet been able to provide documentable evidence to substantiate a marriage in 1770 between Robert Abernathy and Ann Nance (Nantz).
Second: to the best of my knowledge no one has yet been able to provide documentable evidence to substantiate that the Mary Abernathy who married Richard Rocket was the daughter of a specific Robert Abernathy, only that her father was _a_ Robert Abernathy. Mary Abernathy has been listed in various sources as 1) dau of Robert and Sarah Nichols Abernethy, later of Kentucky, but dates wrong. 2) dau of Robert 4th and Sarah Abernathy, dates ok, but NOT mentioned in his will. 3) dau of Robert 3rd and Mary (Miles Harwell), but dates wrong. 4) she could also have been daughter of that either of two South Carolina lineages. and last but not least: 5) she could have been a daughter of one of the newer Scots immigrants, of which an estimated average of 10,000 per year flooded into the colonies, especially the Carolinas. I will grant you that the circumstantial evidence seems to support the possibility that she was a daughter of the 4th Robert, but if so, why was she (or her children) _not_ mentioned in his will?
Third: to the best of my knowledge, no one has yet been able to _prove_ (with documentary evidence) that the Christine who married Robert Abernathy (son of the first Robert of Charles City County VA) was a daughter of either one of her mother's husbands. The evidence (her mother's will) only proves that Christine was married to Robert, had male siblings surnamed Parham _and_ Tilman, and a married sister, whose father could also have been either of her mother's husbands. Christine's maiden name could have been Parham _or_ Tilman and we frankly do not know for sure which.
Sometimes one has to accept not knowing what is buried in the mists of time.