A pile of large stones laying in an open field. James C. Hughes labeled the photograph "Bursting Course." Hughes was stationed at Fort Sill from January 18 to May 18, 1918. He was a student and then from March 22 to May 1 he was an instructor at the School of Fire, Ft. Sill, Oklahoma. A full biography of James Clark Hughes is available at the link below to Kansapedia.