Brendan Riley's Solano Chronicles: How Mare Island was named – Times Herald Online
Mariano Vallejo was a young Mexican Army lieutenant when he led 25 soldiers on a horseback expedition around much of the San Francisco Bay area in about 1830. They traversed what eventually became Oakland, Richmond, Martinez, Crockett, Vallejo, San Rafael and Sausalito, among other cities.
Source: timesheraldonline.com