MV-1A Mount Vernon New York Type. The MV-1A Mount Vernon type salt in clear glass is listed as Scarce by the Neal's and was manufactured at the Boston and Sandwich Glass Company in Massachusetts between 1826 and 1840. The name Mount Vernon type was given to this mold variant because green tinted shards from this mold type were found at Mount Vernon New York. Most of the specimens in this group were manufactured at the Boston and Sandwich Glass factory.