California Gold Rush History: Significant Dates and Discoveries   The following represent the most signficant dates and discoveries of the California Gold Rush:  1848:  In January, James Marshall finds a few small gold nuggets in the mill race of John Sutter’s sawmill at Coloma. The word soon spreads and one of the largest human migrations in history begins as more than 500,000 people descend on the California goldfields in what would later become known as the Motherlode Region. Not long af