 Mabel W. Thomas, who served as assistant librarian and chief reference librarian under Greene, and retired in 1948, began a collection of books, periodicals, and other material that were the foundation of the California Room in the 1940s and now contained in the well-used Oakland History Room.The Main Library has occupied its present location at 125 14th Street near Lake Merritt since 1951.It is one of the largest public library facilities in the Bay Area.