That dent would be unusual to see come off the production line.. but it looks to me like the bottle was partially melted, likely in a trash fire..
The slugplate part of it is inside the inner "seam" where it says "Somerville Branch Somerville NJ" and the shape of it is called a tombstone slugplate.. for obvious reasons.. the rest of the embossing was part of the original mold, and probably used with different slugplates with different specific info..
I agree with cyberdigger (Charles - Thank you) except I believe the dent MAY have occured when the glass was still quite pliable and touched something in the lehr during the cooling process or shortly after the blowing process. I have seen glass objects with similar dents that look as though they were picked up with tongs. However, those usually have dents on opposite sides.
We often see small pieces of glass either added or missing on insulators that the hobby referrs to as "Lehr kisses" when two pieces touch in the lehr.
That is an interesting bottle. Thanks for shareing
I would have to go with botlguy's idea, I have seen many "burn victims" as I call em over the years, and the glass is not clean like your example.
I have seen this before on bottles, but your's might be the most extreme.
Perhaps it slipped in the lipping process and was pinched as a result. Quality control then was not what it is now..........