Complex sentence: Folsom is named for Joseph Libbey Folsom who purchased Rancho Rio de los Americanos from the heirs of a San Francisco merchant William Alexander Leidesdorff, and laid out the town called Granite City, mostly occupied by gold miners seeking fortune in the Sierra Nevada foothills.
Split into simpler sentences: Folsom is named after Joseph Libbey Folsom who purchased Rancho Rio de los Americanos from the heirs of a San Francisco merchant William Alexander Leidesdorff. Folsom laid out a town initially called Granite City, mostly occupied by gold miners seeking fortune in the Sierra Nevada foothills.