Ultima Clayton was the daughter of General Sir William Clayton and his wife Jane, relict of the late Sir Charles Brandon. Ultima was so-named because her father was in his seventies when she was born, and (wrongly) thought he would have no more children. Ultima and her family are discussed by Philip José Farmer in Tarzan Alive.
Ultima married John T. McGee, an Ohio landowner who had been visiting England when they met. In Doc Savage: His Apocalyptic Life, Farmer reveals that Mr. & Mrs. McGee settled in Ohio and had a son whose name he was unable to trace, but who had fathered Travis McGee and a second son who committed suicide.
Subsquently, Wold Newton scholar Brad Mengel revealed in his article "Watching the Detectives, or The Sherlock Holmes Family Tree" (in Myths for the Modern Age, ed. Win Scott Eckert), that Travis McGee's father was named Scott McGee, and that Scott's sister Leslie was the mother of Archie Goodwin. Farmer himself had raised the possibilty that Travis McGee and Archie Goodwin were cousins.