Some areas had stoneware clay, which is stronger because it’s fired at very high temperatures. By the late 1800s, potters had learned to make salt-glazed stoneware with blue decorations. Around 34 potters made items such as crocks, jars, jugs, and canning jars. They often worked in towns along the Monongahela Valley (Bridgeport, Clarksburg, and Morgantown) and in the Ohio Valley (Wellsburg, Wheeling, and Parkersburg).