I am researching a shell casing piece of trench art. What I know so far is that is from the 78th "Lightning" Division. The 308 was an artillary unit in the 78th. The 78th was formed in 1917 at Fort Dix. It was the tip of the spear in the final push against Germany and involved with three campaigns Meuse-Argonne, St. Mihiel, and Lorraine.
The shell is from a 3/50 naval gun with a Mark I designation. (visable in one of the pictures. Any additional information will be appreciated.