Hi Rhona, This jar appears to be the rounded-square version, which according to Dick Roller's Standard Reference was made in the 1940's by the Anchor Hocking Glass Corp. in Lancaster, Ohio. If the jar is in fact round, it would date from 1938-1942. -Tammy
hi tammy, thanks for the information. the jar is round. i use'd to do some canning back in the 70's. maybe when i retire i can do it again. i have some other jars i will post pics of later. seem's strange this jar is older then i am. thanks again, rhona