Hi jimjung
My opinion is as follows...Could be wrong...David will verify if my observations are correct or not.
Not sure if these are Ottawa/Montreal printings without stamps in hand.
STAMP ONE: Scott 35 {Style U - U35}
STAMP TWO: Scott 35 {style H - H35}
STAMP THREE: Scott 35 {style N - N35}
STAMP FOUR: Scott 35 {style T - T35}
STAMP FIVE: Scott 35 {????}
Robert
Here is another variety that is inverted...Below is a block of P6-7-106....Nor recognized in the 6th cancel addition...Stamp is bottom right...

Also there is a huge DOT in the middle of the two bottom stamps.
NAIL HEADS. This type occurs when the "nails" that hold the printing plate become loose and leave an ink impression on the stamp.
