Martha L Hefley b. Aug 10, 1830 in SC

My Gr. Gr. Grandmother was Martha L Hefley Clair b. Aug 10, 1830 in SC. She married Sam Clair about 1870/1871. They had three sons, Zebulon C. Clair 1872, Great Britain Clare 1874, and John Stevenson Clair 1877. They resided in Saline County, AR. I don't believe Hefley was Martha's maiden name. I found her in the 1870 census in Saline County, AR living alone with her daughter, Ginny Hefley, born abt. 1867. This leads me to believe that her husband must have died. I'm trying to figure out her maiden name. The only way I can figure out to do that is to first trace her thru her first husband. Any information would be appreciated.