On the 1850 Dist. 17, GIlmer Co., Virginia Census is GEORGE W BAYNES, age 53, JANE BAYNES, age 45, and MARY BAYNES, age 10.
This could be LAMBERT'S sister - JANE would have been about 35 years old when MARY was born.
There is record of the marriage of MARY BAYNES, age 16, born in Monroe Co., Virginia) to JOHN W HEFNER on Nov. 16, 1854 in Gilmer Co., Virginia.
Hope this helps you in your search! Sincerely, Melinda