John G. Kellogg went to San Francisco on October 12, 1849, from Auburn, New York. At first he was employed by Moffat & Co., and remained with that organization when control passed to Curtis, Perry, and Ward. When the U.S. Assay Office was discontinued, December 14, 1853, Kellogg became associated with G.F. Richter, who had been an assayer in the government assay office. These two set up business as Kellogg & Richter on December 19, 1853.
When the U.S. Assay Office ceased operations, a period ensued during which no private firm was striking gold. The new San Francisco branch mint did not produce coins for some months after Curtis & Perry took the contract for the government (Ward having died). The lack of coin was again keenly felt by businessmen, who petitioned Kellogg & Richter to “supply the vacuum” by issuing private coin. Their plea was soon answered: on February 9, 1854, Kellogg & Co. placed their first twenty-dollar piece in circulation.
The firm dissolved late in 1854 and reorganized as Kellogg & Humbert. The latter partner was Augustus Humbert, for some time identified as U.S. assayer of gold in California. Regardless of the fact that the branch mint was then producing coins, Kellogg & Humbert issued twenty-dollar coins in 1855 in a quantity greater than before.
The 1855 twenty-dollar piece is similar to that of 1854. The letters on the reverse are larger and the arrows longer on one 1854 variety. There are die varieties of both.
In 1855, Ferdinand Gr?ner cut the dies for a round-format fifty-dollar gold coin for Kellogg & Co., but coinage seems to have been limited to presentation pieces. Only 10 to 12 pieces are known to exist. A “commemorative restrike” was made in 2001 using transfer dies made from the original and gold recovered from the SS Central America. These pieces have the inscription S.S. CENTRAL AMERICA GOLD, C.H.S. on the reverse ribbon.