The marks below are images we've captured on ceramics we have owned.
Debolt's Dictionary of American Pottery Marks is another good resource for identifying Ceramics that are white or off-white, often high-fired, including vitreous china and ironstone, and usually used for dinnerware or bathroom sets.
Blue Mountain started with purchased blanks, but began producing red clay bodies with drip glazes around 1953.
The black-green combination is easiest to find and to recognize.
The pottery made plumbing fixtures long before and after the artware production.