Catherine is probably the daughter of Jacob Murph (bca 1740-1750 in SC), d. bet. 1830-40 in Lincoln Co. GA.Jacob first appears in an 1815 land deed in Lincoln County.In a 1777 Berkeley County, SC land deed, there is a Jacob Morff buying acreage that was originally granted to Henry Caver (father of John Caver?).
Jacob is known to have at least two sons, John (1830, 1840 & 1850 Lincoln Co. censuses) and Jacob Jr. (1830, 1840, & 1850 Lincoln Co. censuses) who married Liza Moseley, and possibly a third son, Carnelius, but this is a guess.
This isn't my line, but just some Murff/Murph research.Hope it helps some.