1854 Kellogg & Co. (San Francisco) $20 Gold (Double Eagle)With the imminent opening of the San Francisco Mint, the United States Assay Office ceased operations on December 14, 1853. At that time no private firms were coining gold. The United States Assay Office, under contract to Messrs. Curtis and Perry, was being reconverted to house the authorized United States Branch Mint. The coining ...