The 1840 Census for Washington Co., District of Columbia shows a John Paxton listed directly below William. Living in the house hold are at least 3 grown males including himself. What I have been able to determine from the various marriage records for Paxton women is the couple had at least 8 and possibly nine children. I would look at your families names and see if the name Selman is used for a middle name. My reason is that the Selman family was an early family in Maryland and may have been used as a middle name or given name. The John Paxton on the 1840 census does not appear again. So he either died and is buried in the Methodists Cemetery [we know several burials took place before the ground was deeded] or he moved. If I know who the father of Florida Paxton the girl on the 1850 census was, it might be she was his daughter. I will work on that when I have time. See was living in different households over time.