World War I era Artillery Shell Cone / Head

This is a very large-caliber World War I era Artillery shell cone / head. This is the top of some sort of large-caliber artillery shell, possibly “used” on either a ship or some sort of coastal gun. The shell is about 7-8 inches wide and a little over a foot in height when stood flat. It is heavily rusted, although there are a few numbers barely readable present on one portion of the shell. Otherwise, not much is known about this relic.