In the 1905 incidental score to Peter Pan by John Crook (1852–1922), there’s a notation I’m unfamiliar with: double-beamed notes with unfilled heads. (See the first four bars of the score below.)
In context they appear to be some variant of the quarter note, but is there something about this form I need to know? If I reproduce this score, will any information be lost if I use standard quarter notes (♩) instead?