This might be a good lead, because my James (married to Alice Levering) named a daughter Mary Miller Lawrason, also named a daughter Mercy. I've searched and searched for my James' family, only to come up with Thomas as his father. James and Alice Levering Lawrason are both buried in Christ Church Cemetery, Fairfax County, VA.
Here are the children of James Lawrason (by Alice Levering) that I have:
Thomas b. March 29, 1780 m. Elizabeth Carson Elizabeth b. September 28, 1781 m. Hezekiah Briscoe Smoot Lived in Fairfax-- Alexandria VirginiaMary Miller b. February 17, 1783 m. Aaron Levering (a cousin) John Butcher b. March 15, 1785 d. 1786 Ann Butcher b. February 14, 1787 m. Aaron Righter Levering (another intermarriage) Lived in Baltimore, MD William b. June 13, 1788 d. 1788 Mercy Ann b. October 24, 1789 m. Romulus Riggs Lived in Philadelphia Alice b. February 28, 1792 m. Elisha Riggs (Brother to Romulus) Lived in NY, DC buried in Arlington, VA Susannah b. March 24, 1794 d. 1800 James b. March 15, 1796 d. 1814 Benjamin S. b. June 4, 1799 d. 1800
Let's keep in touch, I'd love to connect my James to your Lawrence.Looks like a branch went up to Ontario...?