Mary was the daughter of Gilbert Falconar (1741-1788), of Kent County, Maryland, by his second wife Mary. Mary's name is unknown to me, but she was the niece of one Charlotte Griffith. Gilbert was the son of Abraham Falconar (d. 1754), who was the son of Gilbert Falconar (1686-1736). Many more details, plus the Scottish ancestry of the family, can be found in my book, _Falconer of Halkerton_, the details of which can be found in another message on this page.
The book lists Mary and David Webb, but I wasn't aware of their children, so they aren't listed.