Warner Brothers has modified their logo more than dozen times over the years, and that specific version of the shield with the hyphen between the W and B, was used just from 1934 to 1937.

You can see a detailed analysis of the many changes they did to their logo here; http://annyas.com/screenshots/warner-bros-logo/

My coincidence, my father was a graphic designer, and he designed the logo they used from the 1970s to the mid-1980s.