Old River ~
My guess is your bottle is one of the following ...
1. Olive
2. Capers (But most capers bottles are a dark emerald green).
3. Pickle
4. Condiment / Mustard / Etc.
And this regarding the Glass Makers Mark ...
O in a square ... Owens Bottle Company, Toledo OH (1903-1929), also Fairmont, WV; Clarksburg, WV, and other plant locations. Owens Bottle Co. Merged with the Illinois Glass Company of Alton, IL in 1929 to form the Owens-Illinois Glass Company. (Julian Toulouse stated this mark was first used in 1911, but according to U.S. Patent & Trademark Office data, Owens claimed first use was not until 1919! Take your pick on which date you will accept :-). See "OWENS".
OWENS ... Owens Bottle Company, Toledo, OH (1903-1929) and it's successor [after the merger with Illinois Glass Company], Owens-Illinois Glass Company (1929-to date). Mark is confirmed on a clear druggist bottle with date code of 1947. Sometimes just the "O" of "Owens" is enclosed within a square. I don't know when this mark was first used during the OBC years, so will have to go with "1903-1929" until further info is uncovered. I believe the mark was used up into the 1950s or '60s by Owens-Illinois, but have no definite info on ending date. See "O in a square."
SBB
