The Anglo-African, August 6, 1864 DEATH OF A BRAVE COLORED SOLDIER. MR. JOHN GRIMAGE, of Allegheny City, Pa., sends us the following letter, which was sent by Capt. Shedon, of the 6th Regiment U. S. Colored Troops, to Mrs. Joanna Taylor, of said city, describing the circumstances under which her son was killed in an action near Petersburg: SPRING HILL, Va., June 19, 1864.      MRS. JOANNA TAYLOR – My Dear Madam: Day before yesterday, Gen. Gilmore made a reconnaissance towards Petersburg, with a force of which our regiment was a part. We left camp the night before; went as…