There is a sparkplug light that used to be just offshore at Portland. It is now at the end of a breakwater. It is shown on the Maine Lights episode of the PBS Series (no, I don't have it memorized, I was just feeling a bit under the weather yesterday, so I watched one of the videos).

Jake (Stephen)

PS- Anybody watching "Storm of the Century" on ABC? They show a light in it, Peggy's Cove. The story is based in Maine.