William Harrison Mosby, brother of John Singleton Mosby, married twice, first to Lucy M. Booth daughter of John Henry and Mary M. Booth, and second to Mary B. Wilson. He had the following children by Lucy M. Booth: Sherman Harrison Mosby, Alfred D. Mosby II, Haveland 'Hal' Booth Mosby, Virginia McLaurine Mosby, Annie Stuart Mosby and Robert Quarles Mosby. There are not children listed for his second wife. This comes from the The John Singleton Mosby Foundation. Maybe this will help you with your mystery.