Ok thanks for the info what kind of closure did the jars use?I agree with WPA-C. It's a condiment or utility jar and I tend to lean toward an olive, pickle or preserves jar. Although the vast majority of olive jars I have uncovered had a smaller diameter, I can't rule that one out. However, it could also have contained products like preserved cherries or strawberries, etc. Anyway, if you're finding a lot of them, it appears to me that they could have used a lot of whatever the jar contained. I don't know if this helped, but a jar like that could have held a lot of different things.
I believe they used a method similar to the milk bottle caps. Someone here could probably tell you the correct terminology.Ok thanks for the info what kind of closure did the jars use?