Thank you both for your corrections. Some of these are my transcription errors from Shanks, but some are errata in Shanks. I'm inclined to take the GEOnet coordinates, since it's a source; except for Canadian locations, where The Atlas of Canada <http://atlas.nrcan.gc.ca/site/english/> is probably more authoritative. So in zone.tab we'd have: AR -2649-06513 America/Argentina/Tucuman Tucuman (TM) CA +624900-0920459 America/Rankin_Inlet Central Time - central Nunavut CA +4843-09434 America/Rainy_River Central Time - Rainy River & Fort Frances, Ontario CA +682059-1334300 America/Inuvik Mountain Time - west Northwest Territor\ ies GL +7029-02158 America/Scoresbysund Scoresbysund / Ittoqqortoormiit with the following UTC offsets during LMT: -01:27:52 America/Scoresbysund -04:20:52 America/Argentina/Tucuman [this is the same as before] -06:08:20 America/Rankin_Inlet -06:18:16 America/Rainy_River -08:54:52 America/Inuvik