Thank you for your answer, I am sure you are right. It is very old because the glass it discolored and has ridges from where it was cooled when it was made.
Also, the logo is one of the very early ones, very swirly if you know what I mean.
Do you know when the first ones came out?
That sounds right. I was born in 50 so I'll keep it. I just aquired it at an estate sale yesterday. I also bought a pyrex pie plate 208 that I looked up in my book and saw it was possibly as early as 1922. I have several old pyrex. just a hobby.
Thanks so much. I will use this service again, I'm sure.