Judy, In P. H. Mell's book " The Genealogy of the Mell Family in the Southern States", p. 6. he says "Copies of the original Land Grants from the English Crown to John Mell have been obtained from the Department of Public Lands Columbia, South Carolina. These grants are dated June 15th., 1677 and October 1685. The latter is given him in right of his wife Elizabeth, so he probably married between those dates".
Your ancestor Mary Ann DuBose Mell is mentioned on p. 46; b. April 3, 1826, m. James E. Lambright August 9, 1843. At the time the book was published(1897), she was living in Brunswick, GA, and had eight children.