An awesome NPR article on the Science behind solving the mystery of slithering stones.
An Icy Solution To The Mystery Of The Slithering Stones
California’s Old Series Trademarks
Check out the California State Archive's collection of California's Old Series Trademarks.
California’s Untold Stories: Gold Rush
A in-depth look at the California Gold Rush with free teaching materials, a lot of awesome artwork, and great historical information.