Possible Clues:

• Any early Charlie Chaplin movie ... and what unpronounced letters in 16-, 21-, 36- and 46-Across spell
• Pre-talkies movie
• Entertainment category that was called 97-Across before talkies
• One was shot, but made no sound
• Chaplin movie, e.g.
• Finest mill made early entertainment
• Old-time movie