Canada 2014 - Empress Of Ireland Stamps

One more item from this series..Asked the girl at the Post Office to save the advertising of this stamp...Nice.

Counter displays are neat.

I'd like to share some more picture related to this Canadian stamp. Attached is an envelope (obviously quite damaged) without stamp (I presume stamp was soaked as it should be after spending weeks into the St-Laurent river), showing this letter was sent from Quebec city (Charlebourg - a suburb now part of Quebec city) and posted 2 days before the Empress sank. the back shows it was recovered by divers from the wreck of the Empress of Ireland, and also shows the "Branch Dead letter Office stamp, dated Sept 15th.
I'll try to get finer picture of the names (addressed to Mrs J Clarke and Mr. W. A ???, 88 ......Rd, Hettering...North..nts, England. Under the location where the stamps was likely present, is the Phone number 531 ring 2.
As you can see, there is a lot of info on this mail memorabilia, and I am looking for any additional insight members of the forum may offer, about the missing letters in the names, addresses etc..

Looks like

Miss J. Clark
c/o
Mr. W. A. -

Possibly a letter written to a daughter, niece or friend that was living with a relative.

I assume no contents, which is too bad.

Gilles le timbre
Why is there a cancel of "Sept. 15th, 1914"...Which is 4 months after the Empress sunk..Why would they cancel it..??

I would think that it took many months for the divers to retrieve the mail bags, sorting through the wreck. I assume the cancel indicates when it reached the dead letter office? Perhaps others have different explanation? (I am not a DLO expert so I may be wrong...)