Saw your post and thought I could help but I did find a problem. When I looked up Louisa Matilda Blackstone; I also found a Louisa Marion Blackstone daughter of John M. Blackstone and Catherine Harvey. or is she the daughter of Argyle Blackston and Sarah Blackston. Argyle was born 1769 and John M. (Milton) Blackstone was born 1781 or 1771 depending on what site you are on.
Louisa Matilda Blackston Olive did die in 1890 in Georgia same cemetery I belive as Abel. Abel died 17 Sep 1884 Find a grave memorial # 140790394 Also on the 1870 Census they have him listed as Abel Oliver born 1803-04 and he is 66 years old and Louisa M was 59 years born 1810-1811.
It also lists Louisa Matilda Blackston Olive as wife of Abel and the daughter of Argyle Blackstone, or John M. Blackston, Someone has messed them up to where you might have to go to the books to find out the truth of who is the daughter of Argyle or John M. I can't give you a simply answer but I can go to the books to find out maybe tomorrow I can go back to see. Thanks for letting me work this. nancy