I'm going out on a limb here, but there were some "Sanitary Dairy" milk bottlers around. Could it be a cream cheese or cottage cheese jar? IDK, just a guess.
Its just a shame you didn't get the lids with them (a two piece metal lid) but they were not likely to have survived. It's listed in "the fruit jar works" as a product jar.
Well, technically, I guess your jar could be considered an unlisted example. While the jar itself is listed in the Red Book, the SCA color is unlisted. Your jar is only listed as a quart in clear glass. Being a jar collector myself, I really like your jar. The more embossing, the better. It's hard enough to dig a nice looking Product Jar, let alone three of them being dug in the same dump. Very nice find(s) indeed!