You're right, it's a Codd bottle!

In 1872 Hiram Codd patented his revolutionary idea of using a marble in a bottle to seal carbonated beverages. The marble sealed against a rubber seal and the pressure of the carbonation held it in place. To open it, you simply pushed the marble down. In the picture you can see an indentation to the right of the marble. That is where the marble rested when you were drinking to prevent it from plugging the opening while you had the bottle tilted up.

Contributed by Mark Holloway
6/04