Mary Baker DeG. daughter of Baker DeG. and Sarah Vass was born 3 Sep 1764 in Lunenburg Co., VA. She married Gideon William Johnson Jr. (as his second wife).
The date of birth of "Mary DeG." said to have been the daughter of William DeG. and Elizabeth Robertson has been given as "ca 1800" and also as b. 1764 (in SC)--the same year of birth as Mary Baker DeG. Johnson. The information I have seen on this Mary is both confusing and contradictory. One version says William Tidwell married Mary DeG. in 1779 and had two sons, William and Benjamin. The son, William DeG. Tidwell, b. 22 Sep 1818 in GA, is said to have married Angelina Westmoreland.
I hope somebody will be able to give you some more accurate information. This has been a topic of discussion for some time; you can find references to the "Marys" at other websites and in printed material (newsletters, etc.)