This resource is not a newspaper, nor a newspaper index; however, it can be a useful resource if you're doing research on California history.
The California Information File was created and is maintained by the California State Library. It is regarded as an important research tools for California history and biography. The original card file was begun in the early 1900s. It contains over 720,000 cards with some 1.4 million references to information in California newspapers, periodicals, county histories and biographical encyclopedias, as well as the California Section's manuscript collections and vertical files. Material cited dates from the 1840's to 1985. The card file was closed in 1985 and the citations were reproduced on microfiche which is available for research in Bancroft Library.
The California Information File has been continued as an online database of over 60,000 records. References are added regularly from newspapers, periodicals, books, manuscript collections, vertical files and other parts of the collection.