The ability to track down african american families before 1870 is often a matter of luck. Isaac and Margaret are listed in Washington Co in 1870 as well with first 2 sons. Isaac listed as 35, Margaret, 30. They are not listed in 1860 as free blacks. Assuming they retained their slave owners names, Horton, there are no 20-25 males listed on the 1860 Washington Co slave schedule. Don't know if relevant or not, but when the Democratic party made its big push to resubjugate the blacks in 1892, Isaac Horton was one of the black populists killed on election day in Augusta.