I'm going to date this postally unused card circa1935-1937. Reason being, the observatory shown is the Mount Wilson Observatory. The iconic Griffith Observatory (think Rebel Without a Cause, and many other movie and TV appearances) was being completed at the time and surely have been on this card had it been around. What else we see here (clockwise-ish from the top left) is City hall, Chinatown, Union Station, the new Federal Courthouse, the L.A. Memorial Coliseum (built for the 1932 Olympics), Pershing Square, a "typical" California bungalow, Pacific Coast Highway & Santa Monica beach and the famous Biltmore Hotel. All looking like a collage of other postcards this publisher could get his hands on!