Nelly's Silver Mine by Helen Hunt Jackson

According to Wikipedia: "Helen Maria Hunt Jackson, born Helen Fiske (October 15, 1830 – August 12, 1885), was a United States poet and writer who became an activist on behalf of improved treatment of Native Americans by the U.S. government. She detailed the adverse effects of government actions in her history A Century of Dishonor (1881). Her novel Ramona dramatized the federal government's mistreatment of Native Americans in Southern California and attracted considerable attention to her cause, although its popularity was based on its romantic and picturesque qualities rather than its political content. It was estimated to have been reprinted 300 times, and contributed to the growth of tourism in Southern California."