...ay 26, 1857 First overland mail leaves St. Louis for San Francisco......Sept. 16, 1858 First overland mail from California arrives at St. Louis twenty-four days eighteen and a half hours from San Francisco ......Oct. 9, 1858 Legislature calls a State convention, that the will of the people may be ascertained and effectuated, but providing that no ordinance of secession should be valid unless ratifi...