Help With Unfamiliar Cancellation On SC 195

Is that a large "D"? My knowledge is slight. Any ideas about the significance of this cancellation?

Here are a few more with different letters. Also some explanatory text from the Royal Philatelic Society of Canada. But still don't know what the letters mean. Any help?



"Duplex cancels were invented to enable envelope postmarks and stamp cancels to be applied in a single action by postal clerks. There are duplex cancels that feature fancy designs, and others that incorporate numbers and letters, with the city of Montreal having been the main user of this type.

"Cancels depicting the Montreal numbers are only found within thick bars. The ones with letters, however, can be found both with thick bars and with thin wavy lines. Numbers 1 to 13 and letters A to J were used."

I think they were for different areas of the city (Montreal).
Maybe each post office had a different letter assigned?

Toronto also used different numbers for various streets/areas.

Just a guess.

Thanks, 3Dadeo. That was my suspicion too, but haven't been able to confirm it. Here's another example. It's a bit unclear but the upper pair's CDS does say Montreal.

Hi

Postal Station.

Hornet

Yes, postal stations in Montreal. They often show up nicely on multiples.