John might possibly have had a daughter named Martha who married Nathaniel Coates and had a daughter Jane Smiley Coates in 1760. Nathaniel Coates was the High Sheriff in Wilkes County, GA. Martha was supposed to be from the "prominent Lamar family of Georgia". Richard Abell, a Federal Judge who authored a book on A. P. Adamson, grandson of Martha and Nathaniel states "Genealogists have concluded that Martha Lamar was the daughter of John Lamar (1713-1785) and his wife Rachel."