Margaret Susan Martin info

Hi, I am looking for info on my great great grandmother, Margaret Susan Martin.  She was born around 1857 and married Floyd J. Martin i 1872.  They lived in Nicholas County, WV and had three children, Samuel W.M., Sarah Lorena, and Fannie L.A. Martin.  I have no info on Margaret Susan's maiden name but was told that she may have been Cherokee.  Thanks for any info.