Professor Josh Kun and a group of his USC students have been combing through the Central Library's "roughly 50,000-piece sheet music collection, identifying and shaping an unprecedented archive of Southern California sheet music – the very first of its kind," and Kun has collected the results (music from about 1850 through the 1950s) into a book and event series called Songs in the Key of Los Angeles, covering roughly "the period of L.A.'s growth from remote outpost into sprawling metropolis," according to a press release. To accompany the project, KCET's Artbound has filmed contemporary LA artists recording some of the old-timey songs (featured: "singer/rapper Aloe Blacc; alternative country group, I See Hawks in L.A.; singer/songwriter, Julia Holter; nouveau-gypsy band, The Petrojvic Blasting Company; and modern-hybrid Latin band, La Santa Cecilia."). Here's I See Hawks in LA performing "In The Valley of the San Joaquin" from 1904. Kun hasn't found any earlier recordings of the song.
Kun also writes a little at KCET about the range of music and history dug up at the library:
Slowly, a SoCal sheet music taxonomy began to emerge: The Sunshine and Oranges song; The You Have No Idea How Badly You Need To Come To California song; The I Was in California But I Left and Boy I Should Never Have Left California song; The My Love Lives in California song; The You Will Find Your Love in California and You Will Compare Her To A Rose or a Poppy song; The Mission Bells Are Chiming For A Fantasy Spanish Past in Old California song; and the This Is Really Just A Jingle for a Furniture Store or a Hotel So After You Buy the Sheet Music Please Come Book a Room or Buy A Piano song. What also began to emerge was a clear portrait of an early bustling Los Angeles music industry that has been rarely commented upon. Most histories of popular music in Los Angeles give the impression that there was nothing going on here before the 1940s--before the labels opened up shop, before Hollywood was in full swing, before Central Avenue was really jumping -- but the Library's sheet music collection reveals a thriving scene of independent music publishers, theaters and vaudeville houses, and music stores, all mostly centered downtown.