texas21 wrote:Xcaliber wrote:<One thing I'd be curious to know is if San Francisco did the cancellations for all the surrounding areas back then.>
San Francisco, San Mateo County, part of Santa Clara County.
So no in office cancellations in that time period?
We looked at this pretty hard about 6 months ago. Apparently correct, typical mail collected in San Francisco, San Mateo County and parts of Santa Clara County--even mail mailed in a slot within a local post office--was all processed and postmarked at Rincon Annex in San Francisco. Exceptions would be a letter handed directly to a window clerk at a local post office, but which apparently did not apply to any of the Zodiac SF letter postmarks. The Sunday hand-postmarks were anomalies, but I believe the consensus was they were still processed and postmarked at Rincon Annex--possibly because the machines weren't operating on a Sunday.
For a while it was thought possible that Mare Island mail was processed at Rincon Annex, but that was apparently incorrect.
As for the general dates of postmark, mailboxes often had 2 pickups a day, morning and afternoon, so it's conceivable a letter mailed in the morning would receive that day's postmark, while a letter mailed in the afternoon might not.
