She doesn't belong to the parents
Richard Welch
Abigail Blackshear Welch
Abigail was born in 1792 and it is nearly impossible for her to be the mother of Rachel, who was born in 1855.
The youngest child of Richard Welch and Abigail Blackshear was born in 1840, when Abigail was 52. That is 15 years earlier than the 1855 birth of Rachel.
I have no idea where Rachel might belong.