Time zone change symbols for maps??

[Figurehead]

Hi all,

I'm brand new as a member, and am trying to figure out a few conundrums regarding a pen and ink map commission I'm doing at the moment. The museum I'm working for would like to have an indication of the time zone change that occurs between the coast of US Maine and the Canadian province of New Brunswick. Does anyone know of historical markings on coastal maps that indicate time zone change?
Thanks,
- Figurehead

[RobA]

This is the only one I've seen:



The world time zone map is a copyrighted production of H.M. Nautical Almanac Office. Reproduction or re-use may require payment of a license fee.
For further information, contact H.M. Nautical Almanac Office, Space Science Department, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UNITED KINGDOM.

-Rob A>