Industrial mineral site no. 1539, known as "Cavanaugh" is a site in King County, Washington. This site has been associated with sandstone. A notation found in DGER Bulletin 37 on page 123 says "Soft gray sandstone containing 76.8 percent silica and 2.2 percent ferric oxide. Washed sand, from which 13 percent clay had been removed, gave medium-gray fusion at cone 18", and designates the value as "Probably suitable for molding use".
