U5 without lines has a light 6 PAID marking across the address. I can't make it out, but looks to say 6 PAID. Would it cost 16 cents to send a letter to Milton On. in 1855? Any help would be appreciated.
The marking is a US Exchange Office marking and reads Paid 6d - the treaty rate to Canada at the time was 10¢ US or 6d Canadian. The marking is just indicating to the Canadian Post Office that the letter was fully paid to destination.