 Complete the following phrase:  Clark was appointed to the US Military Academy at West Point and graduated in 1868. He was assigned as a Second Lieutet with the U.S. 2d Cavalry Regiment, to which he belonged for the remainder of his short career. He joined the staff of General George Crook at the end of August, 1876, when Crook rejoined the columns of General Alfred Terry and Colonel John Gibbon after the Battles of the Rosebud and the 