[tz] Correcting daylight-savings time for central Missouri prior to 1967

[Robert Elz]

    Date:        Fri, 23 Nov 2018 15:52:19 -0500
    From:        Jane Eisenstein <softweave at gmail.com>
    Message-ID:  <7DD1D3F1-2C71-44DB-8794-2967D669D200 at gmail.com>

  | Perhaps. I would have to locate each of the exceptions and see whether any
  | are adjoining. 

If you mean geographically, then no, that's not needed.   What makes a region
is that the clocks set correctly show, and have shown, the same time, alyways,
since  standardised times were introduced (or for definite inclusion in tzdb, since 
1970)    If two areas have always had the same local time, they can be
represented by the same timezone (and would normally be so unless that
looks to be by pure chance with no overriding reason it should be so).
If the local time has ever differed (since 1970, and ideally, though we are not
there yet, since standardied time) then they should be different zones.

kre