GUNTHER & BERNS SHEBOYGAN. (quart)
Quart bottles with a potter's stamp are rare - pottery bottles are almost al=ways marked with the bottlers name. They presumably did this so that multiple bottles could use them and still identify them upon return. One bottler that used them was the Sheboygan Mineral Water Co. for sparkling mineral water. See the www.madefromclay.org article "Eastern Stoneware Co.".