I began by asking,
   "What happened to San Francisco
   between the Gold Rush and the 1906 earthquake?".

   And discovered, to my amazement, that the answer was--
   "The Comstock Lode".

Major Events, 1860-1875

San Francisco... may have been born in the Gold Rush, but it grew to maturity with the flood of silver from the Comstock Lode.
Virginia City... and the Comstock Lode went from barren mountainside to the richest city west of the Mississippi in just 15 short years.
National... the Civil War ended, but a combination of natural and man-made disasters plunged the nation into depression.