The following is a listing of known glass manufacturers and their trademarks that may apply to the Carnival Glass industry. As an example there is some proof that many of the Cambridge pieces were actually iridized at the Millersburg factory. There are many other manufacturers trademarks out there needing put on the list so if you know of one please e-mail with the information so it can be added to the list. Permission is granted to any not for profit organization who wishes to use this article for reprinting in their not for profit newsletter. 1947 - 1978 Moulds sold to Island Mould Co. and mark removed Dorothy Taylor Modern Souvenir pieces.
Bottom line stands for Kansas City, Missouri.
Produces limited edition lines. If there's no number in the oval it was made in 1970's, an 8 in 1980's, and a 9 in 1990's. Glass Co. Unknown Impressed mark. I had no example of mark to go by. All Hansen glass also has a pontil mark on it.