C. Buck, a member of the 79th New York Regiment, confined in the lower prison, near Rockett’s, was shot and instantly killed, about 1 o’clock Saturday morning, by one of the sentinels who kept watch over the building.—The latter observing the Yankee to approach the window in a suspicious manner, as if contemplating an escape, ordered him away several times. To these repeated commands the prisoner returned an insolent and defiant refusal, and the sentinel finally leveled his musket and fired. The ball struck the luckless Lincolnite in the stomach, inflicting a terrible wound, which terminated his life in a very few moments. The sentinel has not only been exonerated from all blame in the matter, but has received the applause of the proper military authorities for his prompt and decisive conduct in carrying out his instructions. The unfortunate Yankee was buried during the evening, in the burial ground at the foot of Third street, set apart for the interment of the Federals who may shuffle off their mortal coils in this locality.It came as a dizzying shock to learn about such a terrible event from the newspaper considering that Lizzie spent so much time at the prison, but it happened that she had not visited the prison in several days.