I have a Mary Ann Roach who married James Thomas. I have no dates but their first child was born in Nov.27, 1857 so the dates would not correspond to your Mary Ann. There may be a connection however. Additional children of James and Mary Ann were Abram, James, Presley, Ann, Mary, Elizabeth, Amanda, Lucy, and America. All were from the Lee County area. Census indicates that James and Mary Ann were originally from Virginia.