This is most likely a Certo Peptin bottle dating between the 1930s and 1940s. The unusual brown glass bottle is embossed along the front with two 1/2 Cup markings and up and down arrows. The bottom of the vintage bottle is embossed "C-85-7". Although this bottle does not have an Owens-Illinois glass mark, similar bottles were produced by them for Certo and embossed with the company name. Best guess is the "C" represents "Certo" and the "7", the year 1937 (Owens Illinois naming protocol). The bottle has a unique, indented front and features a crown top simliar to a beverage bottle top. Certo Peptin was a fruit peptin used in making jelly. My father, an avid bottle digger, found this beautiful bottle in the ruins of an old homestead in Virginia more than 40 years ago. Its in great shape, although there are a couple of small chips above the embossing and a bubble at the rim. Clarity is very nice for a dug bottle. (See photos.) It measures about 7.5" x 2.25".