'A social history of the Spanish-speaking Californians, 1846-1890'; By Leonard Pitt (1966), available at SCPL.
The names are familiar from California street signs: Castro, Vallejo, Berryessa, Bernal. Or, if you grew up in southern California as I did: Pico, Sepulveda, Dominguez, Olvera. These are the names of some of the families who, through huge land grants awarded by the Mexican government, owned much of California in 1846. Pitt's very readable book tracks the declining fortunes of these "Californio" families from the Mexican War into the gold rush, statehood and on through the development boom of the 1880s. There are no direct references to any persons or events in Santa Cruz County, but the larger background of California events during this time period helps to provide context for a better understanding of Santa Cruz history.
