Robinson Wilson Marriage

My great grandparents are CHARLES DAVID WILSON and VIRGINIA ROBINSON married around 1895,I do not know where.VIRGINIA was suppose to be full blooded sioux indian who left nebraska or the dakotas early in 1880s. I have them both listed on a cencus record from 1900 in las cruces, new mexico. I am researching to find out where they both were before 1900 and where they each were born. Also I have a letter of my father and his brothers attending Ft. Mohave Indian School in 1929 in Ft. Mohave, Az.