My g-g-grandmother was Cordelia Anne Gressett, born in Virginia in 1840. In later census records she claims both her parents were born in Virginia as well. I'm wondering if she isn't the sister of your Ellis? She married a soldier from NJ who was sick and being treated in Lee's Arlington house. That's about all I know of her other than that she was definitely French ancestry. I can't find any Gressett, Degrasse, de Gressette, etc. in Virginia during the 1850's or 1860's.